Genetics - New Chapters Final!!
In the nematode worm, C. elegans, embryonic development is controlled largely by controlling _______________. A) Bicoid B) transcription C) post-transcription D) protein processing E) None of the answer options are correct
C) post-transcription
In a population in Hardy-Weinberg equilibrium, what will be the proportion of matings between homozygotes? A) p2 + 2pq B) p4 C) p4 + q4 D) p4 + q4 + 2p2q2 E) 4p2q2
D) p4 + q4 + 2p2q2
The evolutionary history of a group of organisms is called a: A) homology. B) orthology. C) heterology. D) phylogeny. E) synteny.
D) phylogeny.
Retroviruses replicate using: A) DNA polymerase. B) RNA polymerase. C) restriction endonuclease. D) reverse transcriptase. E) topoisomerase
D) reverse transcriptase.
The Ames test is used for determining whether a particular chemical acts as a mutagen. It does this by selecting for: A) new His- mutations in Escherichia coli. B) revertants of His- mutations in Escherichia coli. C) new His- mutations in Salmonella typhimurium. D) revertants of His- mutations in Salmonella typhimurium. E) both revertants and new His- mutations in Escherichia coli.
D) revertants of His- mutations in Salmonella typhimurium.
The class of genes that affect patterning within each segment is the: A) maternal-effect genes. B) gap genes. C) pair-rule genes. D) segment polarity genes. E) Hox genes.
D) segment polarity genes.
Which of the following diseases is/are MOST likely to be caused by excessive exposure to UV light? A) Cockayne syndrome B) Huntington disease C) lung cancer D) skin cancer E) xeroderma pigmentosum
D) skin cancer
A mutation that occurred in a plant petal would be best termed: A) dominant. B) germinal. C) recessive. D) somatic. E) suppressor.
D) somatic.
A morphogen is a molecule that induces: A) cells to undergo cellular division. B) cells to increase in size. C) various responses in surrounding tissue in a non-concentration-dependent manner. D) various responses in surrounding tissue in a concentration-dependent manner. E) None of the answer options are correct.
D) various responses in surrounding tissue in a concentration-dependent manner.
A transversion somewhere within gene "B" in a laboratory plant results in the production of a mutant mRNA that is much longer than the wild type. This transversion is most likely located: A) downstream of the STOP codon, in the last exon of gene "B." B) in an intron of gene "B" away from the splice sites. C) in the open reading frame of gene "B." D) within a splice site of gene "B." E) within the promoter of gene "B."
D) within a splice site of gene "B."
The rare enol form of thymine pairs with guanine. If a thymine enolization occurs during replication, what would be the mutational event? A) AT to TA B) CG to AT C) CG to GC D) GC to TA E) TA to CG
E) TA to CG
The maternal-effect Bicoid gene codes for: A) a signal protein. B) a serine protease. C) a DNA-binding transcription factor. D) a cell-to-cell junction protein. E) a transmembrane protein.
C) a DNA-binding transcription factor.
In an animal bearing the heterozygous inversion ABCDE[*]FGHI / ABGF[*]EDCHI, in one meiocyte, a crossover occurred between the D and E loci and another crossover occurred between the F and G loci. The two crossovers involved the same two chromatids. What will be the proportion of abnormal meiotic products from that meiosis? (Note: [*] = centromere.) A) 0% B) 25% C) 50% D) 100% E) It depends on the distance between D and E and between F and G.
A) 0%
In a population of rats, the relative fitness and frequencies of genotypes at present are: ... What will be the frequency of the h allele in the next generation? A) 0.3 B) 0.4 C) 0.5 D) 0.6 E) 0.7
A) 0.3
After a thorough analysis of the DNA from 150 university students, a small region of the human X chromosome is found to have three SNP sites. Two of those sites have three different variants, while the third site has four. How many different haplotypes were present in each student's cells? A) 1 or 2 B) 3 or 6 C) 10 or 20 D) 32 or 64 E) It is impossible to determine based on this information alone.
A) 1 or 2
In a triploid of genotype B/b/b, what proportion of gametes will be B? A) 1/6 B) 1/4 C) 1/3 D) 1/2 E) 2/3
A) 1/6
In a tetraploid species, an individual with genotype B/b/b/b was crossed with an individual with genotype b/b/b/b. What is the expected genotypic ratio in the offspring? A) 1:1 B) 1:2 C) 1:4 D) 1:8 E) 1:16
A) 1:1
A reciprocal translocation happened between chromosomes 1 and 2 in a wild species of strawberries. Below is a diagram of (unreplicated) chromosomes 1 and 2 for the translocated strain of strawberries. N1 and N2 indicate the normal chromosomes 1 and 2, respectively; T1 and T2 are their translocated counterparts. Which chromosomes must segregate from one another at anaphase I to form viable meiotic products? A) N1 and N2 separate from T1 and T2. B) N1 separates from N2, T1, and T2. C) N1 and T1 separate from N2 and T2. D) N2 and T1 separate from N1 and T2. E) T1 separates from T2, N1, and N2.
A) N1 and N2 separate from T1 and T2.
When considering the rate of nucleotide divergence for a particular gene over time, which of the following has been observed to be true? A) Nonsynonymous mutations will become established less frequently. B) Adenine nucleotides are more readily mutated than other nucleotides. C) Synonymous mutations will become established less frequently. D) Nucleotide changes over time are impossible to measure. E) Only noncoding sequences display change.
A) Nonsynonymous mutations will become established less frequently.
When considering synonymous and nonsynonymous mutations within a population, which of the following is TRUE? A) Nonsynonymous mutations will often be removed by purifying selection. B) Synonymous mutations will often be removed by purifying selection. C) The two types of mutations are not distinguished by purifying selection. D) Only nonsynonymous mutations are known to occur. E) Only synonymous mutations are known to occur.
A) Nonsynonymous mutations will often be removed by purifying selection.
Given below are the genotypic frequencies for a single gene with two alleles for three different populations. AA Aa aa Population 1 0.25 0.50 0.25 Population 2 0.35 0.56 0.09 Population 3 0.49 0.42 0.09 Which of the following is/are NOT correct about these three populations? A) One must assume Hardy-Weinberg equilibrium to calculate the allele frequencies. B) Only two of the populations are in Hardy-Weinberg equilibrium. C) Population 1 is in Hardy-Weinberg equilibrium; the frequency of allele A is 0.5. D) Population 2 is not in Hardy-Weinberg equilibrium; the frequency of allele a is 0.37. E) Population 3 is in Hardy-Weinberg equilibrium; the frequency of allele a is 0.3.
A) One must assume Hardy-Weinberg equilibrium to calculate the allele frequencies.
Which of the following statements is/are TRUE about the P elements of Drosophila? A) P elements are examples of eukaryotic DNA transposons. B) P elements are mobilized when females with these elements are crossed to males that lack them. C) P elements are silenced in M cytotype. D) P elements are examples of eukaryotic DNA transposons that are mobilized when females with these elements are crossed to males that lack them. E) P elements are examples of eukaryotic DNA transposons that are silenced in M cytotype.
A) P elements are examples of eukaryotic DNA transposons.
A triploid of genotype a b/a B/a b is crossed to a triploid of genotype A b/a b/a b. If genes A (a) and B (b) are 20 map units apart, what proportion of the progeny will be phenotypically A B? A) 1/3 B) 1/4 C) 1/6 D) 1/9 E) 1/36
C) 1/6
The genetic frequencies of two separate populations are: AA Aa aa Population 1 .36 .48 .16 Population 2 .33 .33 .33 Population 3 .55 .10 .35 Which of these populations are in Hardy-Weinberg equilibrium? A) Population 1 is in Hardy-Weinberg equilibrium, but populations 2 and 3 are not. B) Population 2 is in Hardy-Weinberg equilibrium, but populations 1 and 3 are not. C) Population 3 is in Hardy-Weinberg equilibrium, but populations 1 and 2 are not. D) Populations 1 and 2 are in Hardy-Weinberg equilibrium, but population 3 is not. E) None of the populations are in Hardy-Weinberg equilibrium.
A) Population 1 is in Hardy-Weinberg equilibrium, but populations 2 and 3 are not.
Which of the following is/are FALSE concerning the comparisons between genetic, physical, and cytogenetic maps? A) The distance between two linked markers... B) Restriction maps, contig maps,... C) In physical maps, the distances between markers... D) The banding patterns of chromosomes ... E) In genetic maps, the distances between...
A) The distance between two linked markers. ...
Which of the following mutations is/are MOST likely to result in cell overgrowth and (eventually) may lead to cancer? A) a gain-of-function mutation in one allele of a proto-oncogene B) a gain-of-function mutation in one allele of a tumor suppressor gene C) a loss-of-function mutation in one allele of a proto-oncogene D) a loss-of-function mutation in one allele of a tumor suppressor gene E) a null mutation in one allele of a proto-oncogene
A) a gain-of-function mutation in one allele of a proto-oncogene
The homeodomain encodes: A) a helix-turn-helix motif. B) an ATP-binding domain. C) a leucine zipper. D) a zinc-finger. E) a protease
A) a helix-turn-helix motif.
E. coli cells that have null mutations in the gene encoding adenine methylase will have: A) a higher spontaneous mutation.... B) the same spontaneous mutation.... C) a lower spontaneous mutation.... D) more double-strand breaks.... E) fewer double-strand breaks....
A) a higher spontaneous mutation....
Balanced polymorphism is illustrated by: A) a situation where the selective pressure enhances the frequency of heterozygotes over homozygotes. B) a situation where the selective pressure enhances the frequency of homozygotes over heterozygotes. C) only situations where disease impacts allele frequency. D) situations where allelic homozygosity is impossible. E) All of the answer options are correct.
A) a situation where the selective pressure enhances the frequency of heterozygotes over homozygotes.
Transposable elements that transpose via an RNA intermediate is known as: A) class 1 elements. B) class 2 elements. C) class 3 elements. D) alpha elements. E) D elements.
A) class 1 elements.
Which of the following chromosomal aberrations can result in unmasking recessive alleles resulting in their expression? A) deletions B) duplications C) inversions D) translocations
A) deletions
In E. coli, a region flanked by two repeats of a sequence such as GTGGTGAA is prone to: A) deletions. B) duplications. C) frameshift mutations. D) missense mutations. E) reversion.
A) deletions.
A plant is homozygous for a point mutation in gene B. This plant produces wild-type B protein in wild-type amounts, but a more detailed analysis reveals that the B mRNA produced by this plant is two nucleotides shorter than wild type. The mutation is most likely a two base-pair deletion: A) downstream of the STOP codon, in the last exon of gene B. B) in an intron of gene B away from the splice sites. C) in the open reading frame of gene B. D) that removed a splice site of gene B. E) within the promoter of gene B.
A) downstream of the STOP codon, in the last exon of gene B.
The most closely related genes either within a single organism or between two different organisms are called: A) homologs. B) orthologs. C) paralogs. D) heterologs. E) alleles.
A) homologs.
The pre-mRNA for Sex-lethal, transformer, and doublesex are: A) identical in both sexes. B) shorter in females. C) shorter in males. D) longer in females. E) longer in males
A) identical in both sexes.
The class of genes required for establishing the anteroposterior axis is the: A) maternal-effect genes. B) gap genes. C) pair-rule genes. D) segment polarity genes. E) Hox genes
A) maternal-effect genes
An excess of nonsynonymous fixed mutations between species is likely due to: A) natural selection. B) random genetic drift. C) a catastrophic event. D) inbreeding. E) immigration.
A) natural selection.
A corn plant is homozygous for a mutant allele that results in no pigment in the seed (i.e., white). The mutant is caused by Ds insertion that often exits late in seed development, when there is an active Ac element in the genome. If there is NO active Ac element, the seeds of this plant will be: A) no pigment (i.e., white). B) pigmented all over. C) white with small spots of pigment. D) white with large spots of pigment. E) weakly pigmented
A) no pigment (i.e., white).
In D. melanogaster, when P cytotype (lab stock) females are crossed to M cytotype (wild) males, the resulting F1 progeny are: A) normal. B) defective. C) normal:defective in a 1:1 ratio. D) normal:defective in a 1:2:1 ratio. E) normal:defective in a 3:1 ratio.
A) normal.
The formation of stripe 2 in a Drosophila embryo is controlled by the binding of four transcription factors to the eve stripe 2 cis-acting regulatory element. This includes: A) one maternal protein and three gap proteins. B) one paternal protein and three gap proteins. C) one pair-rule, one segment-polarity, and two gap proteins. D) two pair-rule and two gap proteins. E) all maternal proteins
A) one maternal protein and three gap proteins.
An autonomous element: A) requires no other elements for its mobility. B) requires one additional element(s) for its mobility. C) is only found in corn (maize). D) is found only in plants. E) None of the answer options are correct.
A) requires no other elements for its mobility.
In southwestern Arizona, the melanocortin 1 receptor mutation-bearing mice (dark hair) are commonly found in: A) rocky lava outcrops. B) stream beds. C) sandy desert regions. D) mixed rodent populations. E) high mountain regions.
A) rocky lava outcrops.
A mutation that changes the codon UAA to the codon UAG in a mammalian cell line is called a(n): A) synonymous mutation. B) suppressor mutation. C) nonsense mutation. D) missense mutation. E) antisense mutation.
A) synonymous mutation.
. In a haploid fungus, a transversion arises in the coding region of a gene necessary for the production of the amino acid leucine. The transversion substitutes the last base in the codon UAC (encoding cysteine), resulting in the stop codon UAG. This substitution will most likely cause: A) the production of a truncated (shortened) protein. B) the production of a truncated (shortened) mRNA. C) the production of a shortened mRNA and of a shortened protein. D) no detectable phenotype. E) inability to grow on medium that lacks cysteine.
A) the production of a truncated (shortened) protein.
When comparing different genomes, "synteny" is defined as: A) the same genes in the same order. B) the same genes in essentially the same order. C) the same genes in reverse order. D) different genes found on similar chromosomes. E) duplication of entire genomes.
A) the same genes in the same order.
The "transcriptome" is defined as: A) the sequence and expression patterns of all transcripts. B) the sequence and expression of all proteins. C) the complete set of all physical interactions (i.e., protein/DNA or protein/protein). D) the complete set of all metabolites. E) None of the answer options are correct.
A) the sequence and expression patterns of all transcripts.
In Drosophila, the vast majority of A-P axis genes that contribute to pattern formation encode: A) transcription factors. B) histones. C) sugar-utilizing enzymes. D) operons. E) ligands.
A) transcription factors.
In a tropical human population in Hardy-Weinberg equilibrium for an autosomal locus determining presence/absence of pigment in the skin, the frequency of albinism (aa) is 1 in 10,000. The frequency of heterozygotes is approximately: A) 1 in 25. B) 1 in 50. C) 1 in 75. D) 1 in 100. E) 1 in 1000.
B) 1 in 50.
In corn R is a gene for red aleurone; its recessive allele r determines colorless aleurone. A cross is made between a diploid r/r female and a trisomic R/r/r male. If pollen grains with extra chromosomes are inviable, the ratio of red to colorless kernels expected in the progeny would be: A) 1 red : 5 colorless. B) 1 red : 2 colorless. C) 1 red : 1 colorless. D) 2 red : 1 colorless. E) 5 red : 1 colorless.
B) 1 red : 2 colorless.
A horticulturist plans to self a plant, then (individually) self each of the F1 plants, and repeat the same procedure until he obtains a plant that is heterozygous at no more than one gene. If the parental plant has 15,000 genes and is heterozygous for all of them, how many generations will this process take? (For the purposes of this question, count the parental plant as "1 generation.") A) 8 generations B) 15 generations C) 30 generations D) 15,000 generations E) 30,000 generations
B) 15 generations
Suppose that a population of 25 black-footed ferrets has an initial heterozygosity (H) of 0.5. How many generations will it take for this population to decline to a heterozygosity of 0.25? A) 1 B) 34 C) 68 D) 100 E) 138
B) 34
In a population of rats, 35% of the individuals are genotypically B/B, 10% are B/b, and 55% are b/b. Assuming there are no mutations, no selection and no migrations, the predicted frequency of the b/b genotype after one generation of random mating is: A) 25%. B) 42.25%. C) 47.5%. D) 55%. E) 57.5%.
B) 42.25%.
For many generations, the following genotypic frequencies were observed in a large population of dinosaurs.... A) 4% B) 8.5% C) 19.7% D) 36.8% E) 44%
C) 19.7%
You are studying an X-linked trait. There are two alleles, one showing complete dominance over the other. In females, 84 percent show the dominant phenotype. What percentage of the males will show the dominant phenotype, assuming that individuals in this large population mate at random with respect to this trait? A) 84 B) 60 C) 40 D) 36 E) 16
B) 60
There are ______ Hox genes in Drosophila melanogaster. A) 12 B) 8 C) 10 D) 25 E) 39
B) 8
During mutagenic treatment with nitrous acid, an adenine deaminates to form hypoxanthine, which bonds like guanine. The mutational event would be: A) AT to CG. B) AT to GC. C) AT to TA. D) GC to AT. E) GC to TA.
B) AT to GC.
Which of the following features do bacterial and corn transposons not have in common? A) Both may cause unstable mutations. B) Both may carry drug resistance genes in natural populations. C) Both may have inverted repeats. D) Both may move to new loci. E) Both may cause rearrangements
B) Both may carry drug resistance genes in natural populations.
Which of the following diseases is/are LEAST likely to be caused by excessive exposure to UV light? A) Cockayne syndrome B) Huntington disease C) lung cancer D) skin cancer E) xeroderma pigmentosum
B) Huntington disease
Which of the following are requirements for evolution by natural selection? I environmental change II differential survival and reproduction III heritability of phenotypic variation IV variation in phenotype V sexual reproduction A) II, III, V B) II, III, IV C) I, II, IV D) III, IV, V E) II, IV, V
B) II, III, IV
Which of the following statements is/are TRUE about the miniature inverted repeat transposable elements (MITEs) ? A) MITEs are examples of retrotransposons. B) MITEs are examples of DNA transposons. C) MITEs can attain very high copy numbers in humans. D) MITEs contain transposase gene. E) None of the answer options are correct.
B) MITEs are examples of DNA transposons.
Why don't we find different human populations with different fixed alleles at a certain locus? A) Inbreeding is high. B) Migration between populations is high. C) The mutation rate is lower than the critical value. D) Population sizes are too large. E) Allelic variation is low.
B) Migration between populations is high.
In a haploid fungus, genes a and b are located on chromosome 2 and 7, respectively. A cross is performed between a strain that is genotypically a; b and has normal chromosomes, and a strain that is genotypically wild type but has a reciprocal translocation between chromosomes 2 and 7. If crossing over never occurs in this fungus, what is the expected proportion of tetrads resulting from the cross? Tetrad 1 Tetrad 2 Tetrad 3 Tetrad 4 Tetrad 5 Spore 1 aborted a; b A; B A; B A; B Spore 2 aborted a; b A; B A; B aborted Spore 3 aborted aborted aborted a; b a; b Spore 4 aborted aborted aborted a; b aborted A) All five tetrads will be present, in equal proportions. B) Only tetrads 1 and 4 will be present, in a 1:1 ratio. C) Only tetrads 2 and 3 will be present, in a 1:1 ratio. D) Only tetrads 2, 3, and 5 will be present, in a 1:1:2 ratio. E) Only tetrad 5 will be present.
B) Only tetrads 1 and 4 will be present, in a 1:1 ratio.
In the plant genus Triticum there are many different polyploid species, as well as diploid species. Crosses were made between three different species, and hybrids were obtained. The meiotic pairing was observed in each hybrid and is recorded in the following table. (A bivalent is two homologous chromosomes paired at meiosis, and a univalent is an unpaired chromosome at meiosis.) Species crossed to make hybrid Pairing in hybrid 1. T. turdigum × T. monococcum 7 bivalents + 7 univalents 2. T. aestivum × T. monococcum 7 bivalents + 14 univalents 3. T. aestivum × T. turdigum 14 bivalents + 7 univalents The first cross suggests a diploid and tetraploid individual were involved with one set of 7 chromosomes in common. Based on the other crosses, which species is the likely diploid individual? A) T. turdigum B) T. monococcum C) T. aestivum D) T. turdigum or T. monococcum
B) T. monococcum
Which of the following statements is/are FALSE about Tc1 elements found in C. elegans? A) Tc1 elements are retrotransposons. B) Tc1 elements can transpose only in somatic cells. C) Tc1 elements were used to study the RNAi based silencing mechanisms. D) Single Tc1 element can trigger the silencing of all copies of Tc1 elements in the C. elegans genome. E) None of the answer options are correct.
B) Tc1 elements can transpose only in somatic cells.
In the following pedigree, the shaded symbols represent a rare X-linked disease of the blood. The propositus has 45 chromosomes and is sterile. Propose a single mechanism to account for both the sterility and the blood disease in this female. A) The woman's father was a carrier for the disease on his X chromosome. B) The woman is likely demonstrating a case of Turner syndrome. C) The woman is likely demonstrating a case of Down syndrome. D) The woman's mother's eggs likely experienced a nondisjunction event.
B) The woman is likely demonstrating a case of Turner syndrome.
A pure line of plants of genotype a/a; b/b; c/c; d/d; e/e (all recessive to wild type) was crossed to a wild type. One F1 individual expressed the recessive alleles d and e. This individual arose most likely from: A) a deletion in the quadruple homozygous recessive parent. B) a deletion in the wild-type parent. C) a gene mutation in the wild-type parent. D) position effect variegation in the F1. E) a reversion in the quadruple homozygous recessive parent.
B) a deletion in the wild-type parent.
The molecular basis of sickle cell hemoglobin is: A) a frameshift mutation. B) a single nucleotide substitution. C) a translocation event. D) a virus induced inversion. E) exposure to a chemical mutagen.
B) a single nucleotide substitution.
What term could be used to describe the type of selection occurring with the sickle-cell and normal hemoglobin alleles among areas where malaria is present? A) directional selection B) balancing selection C) stabilizing selection D) genetic drift E) inbreeding depression
B) balancing selection
In fruit flies, mutations in cis-acting regulatory sequences are associated with: A) abnormal functioning of operator sequences. B) body form/color variations. C) changes in fruit fly behavior. D) changes in reproductive fitness. E) an alteration of DNA replication.
B) body form/color variations.
Transposable elements that are comprised of DNA transposons are known as: A) class 1 elements. B) class 2 elements. C) class 3 elements. D) alpha elements. E) D elements.
B) class 2 elements.
The fitness advantage of the "AS" allelic combination can be calculated by: A) measuring O2-carrying capacity in the blood of "AS" individuals. B) comparing the actual frequency of "AS" to the frequency predicted by the Hardy-Weinberg equation. C) measuring the frequency of "AS" in the population. D) infecting the blood of "AS" individuals with the parasite. E) measuring the frequency of "AA" and subtracting that value from the frequency of "AS."
B) comparing the actual frequency of "AS" to the frequency predicted by the Hardy-Weinberg equation.
In D. melanogaster, when M cytotype (lab stock) females are crossed to P cytotype (wild) males, the resulting F1 progeny are: A) normal. B) defective. C) normal:defective in a 1:1 ratio. D) normal:defective in a 1:2:1 ratio. E) normal:defective in a 3:1 ratio.
B) defective.
Sanger DNA sequencing determines the nucleotide sequence because: A) dideoxy nucleotides are incorporated into a growing DNA strand. B) dideoxy nucleotides terminate the growing DNA strand. C) PPi is incorporated into the growing DNA strand. D) PPi is released from the growing DNA strand. E) None of the answer options are correct.
B) dideoxy nucleotides terminate the growing DNA strand.
Which of the following reduce heterozygosity? A) migration B) directional selection C) large population size D) balancing selection E) mutation
B) directional selection
Bacterial transposon structure can be thought of as: A) IS sequences flanked by inverted drug-resistance genes. B) drug-resistance gene(s) flanked by IS elements. C) drug-resistance gene(s) flanked by a pair of mu () phage. D) a mu () phage flanked by two IS elements. E) resistance gene(s) flanked by inverted resistance transfer factors (RTFs).
B) drug-resistance gene(s) flanked by IS elements.
Proto-oncogenes are genes that: A) always mutate into cancer-promoting oncogenes. B) encode very important proteins involved in processes such as the control of cell cycle. C) encode very important proteins that promote apoptosis. D) in their recessive form can act to promote cell cycle progression. E) normally promote oncogenesis.
B) encode very important proteins involved in processes such as the control of cell cycle
In E. coli, a region of a gene with repeats of the sequence CTGG will be prone to: A) deletions. B) frameshift mutations. C) missense mutations. D) reversion. E) triplet expansion.
B) frameshift mutations.
The class of genes required for establishing the formation of a contiguous block of segments is the: A) maternal-effect genes. B) gap genes. C) pair-rule genes. D) segment polarity genes. E) Hox genes.
B) gap genes.
Two chromosomes having the same combination of alleles at multiple loci are said to be of similar: A) genotype. B) haplotype. C) phenotype. D) sporotype.
B) haplotype.
All eight Drosophila Hox genes encode proteins containing a highly conserved 60-amino-acid domain called the: A) hox box. B) homeodomain. C) hox domain. D) heterodomain. E) chromodomain
B) homeodomain.
In the developing chick vertebral limb bud, the zone of polarizing activity (ZPA) organizes a pattern along the anteroposterior axis. Transplantation of the ZPA from a posterior to anterior position: A) causes no change in development. B) induces extra digits with reverse polarity. C) induces extra digits with the same polarity. D) induces extra limbs. E) None of the answer options are correct.
B) induces extra digits with reverse polarity.
Genes with products provided by the female to the egg are called: A) paternal-effect genes. B) maternal-effect genes. C) sex-linked genes. D) embryo-specific genes. E) egg-specific genes.
B) maternal-effect genes.
E. coli cells that have null mutations in the gene encoding mutH will be defective in: A) base excision repair. B) mismatch repair. C) recombinational repair. D) SOS repair. E) thymine dimer splitting.
B) mismatch repair.
Which of the following processes will increase genetic variation within populations? A) incompatible selection B) mutation C) directional selection D) asexual reproduction E) genetic drift
B) mutation
The fluctuation test of Luria and Delbruck showed that: A) a selecting agent can affect mutation rate in E. coli. B) mutations can arise spontaneously before exposure to the selecting agent. C) mutations in E. coli occur at a relatively high frequency. D) the mutation rate in E. coli fluctuates greatly from one generation to the next. E) the T1 phage can act as a mutagen as well as a selecting agent in E. coli.
B) mutations can arise spontaneously before exposure to the selecting agent
The diagram below shows the chromosomes of a plant that is heterozygous at six loci as well as for a reciprocal translocation involving the chromosomes that carry these loci. This plant is crossed to a plant with normal chromosomes that is homozygous recessive at all loci, and the progeny was comprised of about 250 individuals, half of them phenotypically ABDEFG and half abdefg. This result suggests that: A) multiple crossovers occurred. B) no crossovers occurred. C) segregation was always adjacent. D) segregation was always alternate. E) the six loci are unlinked.
B) no crossovers occurred.
A mutation does not affect the length of a gene but results in an abnormally short protein. The mutation is most likely of a type called: A) silent. B) nonsense. C) missense. D) frameshift. E) deletion.
B) nonsense.
Establishment of the dorsal-ventral axis of the Drosophila embryo: A) involves the production of localized DL mRNA on the ventral side of the developing embryo. B) occurs via at least two paracrine signals transmitted between the developing oocyte and the surrounding somatic follicle cells. C) involves the zygotically expressed DL morphogen. D) depends on the activity of anterior-posterior morphogens, such as BCD or HB-M. E) None of the answer options are correct.
B) occurs via at least two paracrine signals transmitted between the developing oocyte and the surrounding somatic follicle cells.
In homeotic mutants: A) one body structure is missing. B) one body structure has been changed into another. C) one body structure has been duplicated. D) one body structure has significantly increased in size. E) the organism is infertile.
B) one body structure has been changed into another.
Genes that have been inherited from a common ancestor are called: A) homologs. B) orthologs. C) paralogs. D) heterologs. E) alleles.
B) orthologs.
If an incorrect base is incorporated during DNA synthesis and is not corrected by DNA polymerase, it can be corrected by postreplication repair. Postreplication repair does NOT involve which of the following? A) detection of the mismatch B) photoreactivation repair C) a process similar to excision repair D) recognition of the methylation status of the DNA strands E) recombinational repair
B) photoreactivation repair
The neutral theory of evolution proposed that most genetic mutations are functionally neutral or nearly neutral. Neutral mutations would be fixed in a population by: A) natural selection. B) random genetic drift. C) balancing selection. D) asexual reproduction. E) the invariance of DNA.
B) random genetic drift.
A nonautonomous element: A) requires no other elements for its mobility. B) requires additional element(s) for its mobility. C) is only found in corn (maize). D) is found only in plants. E) None of the answers are correct.
B) requires additional element(s) for its mobility.
Which of the following conditions results in the faster evolution of a population? A) mutation B) selection C) non-random mating D) natural disaste
B) selection
An adaptive walk of beta-lactamase in response to selective pressure exerted by cefotaxime likely involved: A) the random generation of five changes that provide microbial resistance to the antibiotic. B) sequential changes in single amino acids that each provided an incremental level of resistance to the antibiotic. C) increased genetic change induced by selective pressure exerted by the antibiotic. D) one clear beneficial change and several non-impactful changes in the gene. E) major shifts in the metabolic pathways in the microbe under selection.
B) sequential changes in single amino acids that each provided an incremental level of resistance to the antibiotic.
When considering hemoglobin alleles, scientists concluded that the proportions of the two alleles within a population was strongly affected by: A) the severity of malaria. B) the atmospheric pressure of O2. C) the rate of elimination of harmful HbS alleles. D) the nutritional intake of each individual. E) the severity of malaria and the rate of elimination of harmful HbS alleles.
B) the atmospheric pressure of O2.
The homeotic, gap, pair-rule, and segment polarity genes all control: A) aspects of anterior-posterior pattern formation. B) the number of segments. C) the developmental fates (identities) of the individual segments. D) dorsal-ventral pattern formation. E) the production of the anterior-posterior morphogens.
B) the number of segments.
The "proteome" is defined as: A) the sequence and expression patterns of all transcripts. B) the sequence and expression of all proteins. C) the complete set of all physical interactions (i.e. protein/DNA or protein/protein). D) the complete set of all metabolites. E) None of the answer options are correct.
B) the sequence and expression of all proteins.
A meiocyte of an organism heterozygous for a reciprocal translocation goes through meiosis and results in four viable meiotic products. The most likely explanation is that: A) there was adjacent segregation. B) there was alternate segregation. C) a suppressor mutation occurred. D) the translocation breakpoints were very close to the centromeres. E) the translocation reverted.
B) there was alternate segregation.
The first eukaryotic transposable elements to be characterized at the molecular level were identified within the genes of which organism? A) corn B) yeast C) E. coli D) mouse E) human
B) yeast
In a population, the D d mutation rate is 4 10-6. If p = 0.8 today, what will p be after 50,000 generations? A) 0.1 B) 0.25 C) 0.65 D) 0.8 E) None of the answer options are correct.
C) 0.65
The nematode worm Caenorhabditis elegans is comprised of approximately ______ somatic cells. A) 10 B) 100 C) 1,000 D) 100,000 E) 100,000,000
C) 1,000
Some forms of cleft palate are caused by recessive alleles of a gene on the X chromosome. In an Icelandic population, 3.6 10-3 of the females have this form of cleft palate. What proportion of the males would you expect to be affected, assuming Hardy-Weinberg equilibrium? A) 1.3 105 B) 3.6 103 C) 1.6 103 D) 6.0 102 E) 0
C) 1.6 103
The genome of Hemophilus influenzae, the first free-living organism to have its genome sequenced, is how large? A) 0.5-megabase B) 1.0-megabase C) 1.8-megabase D) 12-megabase E) 18-megabase
C) 1.8-megabase
What is the inbreeding coefficient for individual "B" in the following pedigree? A) 1/8 B) 1/16 C) 1/32 D) 1/64 E) 1/256
C) 1/32
Suppose that in a certain diploid fish genes A and T are on chromosomes 4 and 7, respectively. A female fish is heterozygous at both loci and is also heterozygous for a reciprocal translocation between chromosomes 1 and 4. The translocation breakpoint on chromosome 4 is 10 map units away from the a allele (A is located on the normal chromosome 4). If this female is crossed to a male of genotype a/a; t/t and with normal chromosomes, what percentage of the progeny is expected to be phenotypically A; T and have only normal chromosomes? A) 0% B) 2.5% C) 22.5% D) 25% E) 45%
C) 22.5%
The human genome is comprised of how many base pairs (bp)? A) 1 billion B) 2 billion C) 3 billion D) 4 billion E) 5 billion
C) 3 billion
The strategy for obtaining a genomic sequence can be divided into four steps: 1) overlap contigs for complete sequence, 2) sequence each fragment, 3) cut many genome copies in to random fragments, and 4) overlap sequence reads. What is the order of the four steps? A) 1, 2, 3, and 4 B) 4, 3, 2, and 1 C) 3, 2, 4, and 1 D) 3, 2, 1, and 4 E) 2, 4, 3, and 1
C) 3, 2, 4, and 1
If 64% of the people in a population are blue-eyed and the population is in Hardy-Weinberg equilibrium, what is the percentage of heterozygotes in the population? A) 16% B) 20% C) 32% D) 36% E) It is impossible to make an estimate from these data.
C) 32%
Sequencing of a pine tree population reveals four variants of a particular SNP. Eighty percent (80%) of the trees have the G, 15% the A, 3% the T, and 2% the C variant. What is the genetic diversity of the pine tree population with respect to this SNP? A) 0.007% B) 2.0% C) 33.6% D) 66.4% E) 80%
C) 33.6%
n the flowering plants (the angiosperms), the process of double fertilization occurs. This is where one sperm nucleus from the pollen grain fertilizes the egg, and the other fuses with the two polar nuclei in the female gametophyte to produce the triploid (3n) endosperm tissue. The aleurone layer (the outer layer of cells of the endosperm) can be colored or colorless. The allele C causes color (purple), and the allele c gives colorless aleurone. A plant is of genotype Cc and self-pollinates. What ratio of colored to colorless aleurone layered endosperms are expected in the progeny? A) 1:1 B) 2:1 C) 3:1 D) 10:1
C) 3:1
In a triploid of genotype B/b/b, what proportion of gametes will be B? A) 1/6 B) 1/4 C) 1/3 D) 1/2 E) 2/3
C) 4
. The n + 1 female gametophytes (embryo sacs) produced by trisomic plants are usually more viable than the n + 1 male gametophytes (pollen grains). If 50% of the functional embryo sacs of a selfed trisomic plant are n + 1 but only 10% of the functional pollen grains are n + 1, what percentage of the offspring will be diploid? A) 0 B) 5 C) 45 D) 90
C) 45
A Neurospora nonsense mutation known to be UAG is treated with two compounds, hydroxylamine and 5-bromouracil. Hydroxylamine (HA) causes G·C → A·T transitions, while 5-bromouracil causes T·A → C·G transitions. Which of these agents do you expect to induce revertants? A) Both agents are expected to induce revertants. B) Both agents are expected to induce revertants, but hydroxylamine will be more effective. C) 5-bromouracil only is expected to induce revertants. D) Hydroxylamine only is expected to induce revertants. E) Neither hydroxylamine nor 5-bromouracil agents are expected to induce revertants.
C) 5-bromouracil only is expected to induce revertants.
What percentage of the human genome is derived from transposable elements? A) less than 5% B) 25% C) 50% D) 75% E) nearly 100%
C) 50%
Which of the following scientists discovered the Ac-Ds transposable elements in maize? A) Marcus Rhoades B) Rollins Emerson C) Barbara McClintock D) George Beadle E) All of these scientists made the discovery.
C) Barbara McClintock
Four clones (A, B, C, and D) of human genomic DNA are tested for sequence-tagged sites 1 through 5. A shows 2 and 3; B shows 2 and 5; C shows 1 and 5; D shows 3 and 4.What is the order of the clones in their contig? A) ABCD B) BDAC C) CBAD D) ACBD E) DCAB
C) CBAD
n humans, males have only one X chromosome and females have two, yet housekeeping X chromosome genes are expressed in roughly equal amounts in males and females. How can this be explained? A) The X chromosome is hyperactivated in males. B) The X chromosomes are hypoactivated in females. C) One X chromosome in females is inactivated. D) The Y chromosome in males actually contains similar genes as the X chromosome.
C) One X chromosome in females is inactivated.
Which of these principles of evolution, as described by Darwin's theory, is correctly matched with its role in evolution? A) Principle of variation: Offspring must resemble... B) Principle of selection... C) Principle of variation: Variation in morphology... D) Principle of heredity:... E) None of the answer options are correct.
C) Principle of variation: Variation in morphology...
What is meant by "codon bias"? A) Codons are specific for the amino acids they specify. B) Certain viruses like to infect particular DNA sequences in our genome. C) Some organisms will use specific codons for amino acids they specify. D) Certain viruses like to infect particular DNA sequences in our genome, and some organisms will use specific codons for amino acids they specify. E) None of the answer options are correct.
C) Some organisms will use specific codons for amino acids they specify.
In rabbits, genes T and R are located on the same chromosome, 20 map units apart. A colleague sends you one of his pure-breeding t r/t r males, which you cross to a T R/T R individual. Each of the T R/ t r F1 heterozygotes is then crossed back to your colleague's double homozygous recessive. Altogether, the backcrosses produce 50 rabbits, of which 24 are T R/t r, 24 are t r/t r, 1 is T r/t r and 1 is t R/t r. Which of the following explanations best justifies the results? A) The colleague's rabbit is heterozygous for an inversion that spans at least 16 map units of the region between genes t and r. B) The colleague's rabbit is heterozygous for an inversion that spans at least 18 map units of the region between genes t and r. C) The colleague's rabbit is homozygous for an inversion that spans at least 16 map units of the region between genes t and r. D) The colleague's rabbit is homozygous for an inversion that spans at least 18 map units of the region between genes t and r. E) The colleague's rabbit carries an inversion that spans the whole region between genes t and r.
C) The colleague's rabbit is homozygous for an inversion that spans at least 16 map units of the region between genes t and r.
Wichman and colleagues examined adaptive walks using: A) antibiotic selection on bacteriophage populations. B) bacteriophage infection of mutation-bearing bacteria. C) a bacteriophage and two different host cell types. D) mutagenic compounds delivered to rapidly dividing phage virions. E) None of the answer options are correct.
C) a bacteriophage and two different host cell types.
The spontaneous reversion rate for a chemically induced mutation is 1 × 10-8. For EMS , the rate is 0.9 × 10-8, and for acridine, it is 2 × 10-5. What change was involved in the original mutation? A) an AT to CG transversion B) an AT to GC transition C) a frameshift mutation D) a GC to AT transition E) a GC to TA transversion
C) a frameshift mutation
Hybridization of single-stranded wild-type DNA with DNA from mutations caused by IS elements characteristically shows (through electron microscopy): A) chi structures. B) unpaired tails. C) a single-stranded loop representing IS DNA. D) a single-stranded loop representing wild-type DNA. E) theta structures.
C) a single-stranded loop representing IS DNA.
If the frequency of the recessive allele that causes phenylketonuria (PKU)... A) about 0.0001 B) about 0.01 C) about 0.0198 D) about 0.99 E) It is impossible to make an estimate.
C) about 0.0198
The fungal cross ad, pan × +, + (where ad and pan are two linked loci) gave only the following two types of tetrads: Tetrad 1 Tetrad 2 Spore 1 ad, pan ad, pan Spore 2 aborted ad, + Spore 3 aborted +, pan Spore 4 +, + +, + These results suggest: A) a deletion in the wild-type parent. B) a duplication in one or both parents. C) an inversion in one of the parents. D) a translocation in one of the parents, with adjacent segregation. E) a translocation in one of the parents, with alternate segregation.
C) an inversion in one of the parents.
Some of the most striking and best understood examples of morphological divergence are found in: A) populations of antibiotic resistant bacteria. B) virology. C) animal body-color patterns. D) mouse eye-color mutants. E) blood-type examples in mammals.
C) animal body-color patterns.
In Drosophila melanogaster, Hox genes are: A) clustered into operons. B) clustered in one large gene complex. C) clustered together in two gene complexes. D) clustered together in three gene complexes. E) evenly distributed throughout the genome.
C) clustered together in two gene complexes.
LINEs differ from retrotransposons in that LINEs do not: A) encode transposase. B) encode reverse transcriptase. C) contain LTRs. D) transpose in a replicative manner. E) contain the transposase gene.
C) contain LTRs.
Drosophila melanogaster development proceeds in which of the following stages? A) egg-segmented embryo-pupa-larva-adult B) segmented embryo-egg-pupa-larva -adult C) egg-segmented embryo-larva-pupa-adult D) egg-larva-segmented embryo -pupa-adult E) segmented embryo-larva-egg-pupa-adult
C) egg-segmented embryo-larva-pupa-adult
The doublesex (dsx) gene plays a central role in governing the sexual identity of somatic (non-germ-line) tissue. Null mutations in dsx cause: A) males to develop as females. B) females to develop as males. C) females and males to develop as intermediate intersexes. D) only females to develop as intermediate intersexes. E) None of the answer options are correct
C) females and males to develop as intermediate intersexes.
In human populations, the "AS" allele arose from: A) the insertion of a mutagenic transposon into the Hb gene. B) one individual located in central Africa. C) five independent events, in separate populations. D) a frameshift mutation in the Hb gene. E) a plasmodium-induced change in DNA sequence.
C) five independent events, in separate populations.
Plasmodium falciparum is a parasitic protist that can be carried among host organisms by a mosquito. Infection generates anemia via a process of: A) infecting the bone marrow of its hosts. B) causing uncontrolled bleeding from tissues. C) invading red blood cells and dividing within them. D) mosquito-based feeding upon the blood during transmission. E) anemia is not a symptom of Plasmodium infection.
C) invading red blood cells and dividing within them.
Eukaryotic retrotransposons such as Ty1 and Copia are flanked by: A) direct repeats (DRs). B) inverted repeats (IRs). C) long terminal repeats (LTRs). D) long inverted repeats (LIRs). E) None of the answer options are correct.
C) long terminal repeats (LTRs).
A gene or a trait is said to be polymorphic if: A) the allele frequency is about 50:50 for each of its alleles present in the population. B) the allele frequency of one allele is higher than that of all others. C) more that one form (morph or allele) exists in the population. D) one of its alleles occurs at a frequency lower than 1%. E) only one form exists in the population
C) more that one form (morph or allele) exists in the population.
Sequencing of a population of 110 dogs has revealed nine polymorphic sites within a small region of chromosome 11. All four possible variants were observed for each site. Based on these data, one can say that: A) all the dogs in the sample population have different haplotypes. B) different haplotypes have different frequencies in the sample population. C) not all possible haplotypes are present in the sample population. D) the sample population is not representative of the entire population. E) some of the dogs in the sample population have the same haplotype.
C) not all possible haplotypes are present in the sample population.
Which of the following best describes the frequency of alleles in a Hardy-Weinberg population? A) p2 B) q2 C) p + q D) 2pq E) None of the answers options are correct.
C) p + q
The class of genes required that act at a double-segment periodicity is the: A) maternal-effect genes. B) gap genes. C) pair-rule genes. D) segment polarity genes. E) Hox genes.
C) pair-rule genes.
A wild-type chromosome can be represented as ABC[*]DEFGH, and from this a chromosomal aberration arises that can be represented ABC[*]DEGFH, where [*] represents the centromere. This aberration is known as a: A) deletion. B) duplication. C) paracentric inversion. D) pericentric inversion. E) translocation.
C) paracentric inversion.
Genes that are related by gene-duplication events within the same genome are called: A) homologs. B) orthologs. C) paralogs. D) heterologs. E) alleles.
C) paralogs.
In a classical genetic experiment, Newcombe spread E. coli cells on complete medium. After several generations of growth, he replica-plated the colonies onto two plates with complete medium plus a selective agent. Colonies on the first replica were left untouched, while on the second replica, they were respread, allowing bacteria from each colony to be "moved" to a new location on the plate. Significantly more mutants after spreading (resistant to the selective agent) were observed than if they had not been respread. The experiment was used to: A) demonstrate how to screen for environmental mutagens. B) demonstrate that in some cases mutations are caused by the selective agent itself. C) provide evidence that mutations occur in the absence of the selective agent. D) provide evidence that mutation occurs in prokaryotes as well as in eukaryotes. E) show a direct correlation between the amount of the selective agent used and the number of resistant mutants.
C) provide evidence that mutations occur in the absence of the selective agent.
A point mutation in a gene's promoter will most likely cause the production of: A) a shortened mRNA and a truncated protein. B) a shortened mRNA and a wild-type protein. C) reduced amounts of mRNA and protein. D) reduced amounts of mRNA and wild-type amounts of protein. E) wild-type amounts of mRNA and reduced amounts of protein.
C) reduced amounts of mRNA and protein.
The early Drosophila embryo has multiple nuclei within a single cytoplasm and is considered a: A) coenocyte. B) hyphae. C) syncytium. D) chorion. E) None of the answer options are correct
C) syncytium.
The "interactome" is defined as: A) the sequence and expression patterns of all transcripts. B) the sequence and expression of all proteins. C) the complete set of all physical interactions (i.e., protein/DNA or protein/protein). D) the complete set of all metabolites. E) None of the answer options are correct.
C) the complete set of all physical interactions (i.e., protein/DNA or protein/protein).
In a haploid fungus, a small in-frame deletion arises in the coding region of a gene necessary for the production of the amino acid leucine. The deletion removes the three base pairs corresponding to a UAC codon (encoding cysteine). This small deletion will most likely cause: A) the production of a truncated (shortened) protein. B) the production of a truncated (shortened) mRNA. C) the production of a shorter mRNA and of a shorter protein. D) no detectable phenotype. E) inability to grow on medium that lacks cysteine.
C) the production of a shorter mRNA and of a shorter protein.
The principle of parsimony refers to: A) the most complicated explanation involving the smallest number of evolutionary changes. B) the most complicated explanation involving the largest number of evolutionary changes. C) the simplest explanation involving the smallest number of evolutionary changes. D) the simplest explanation involving the largest number of evolutionary changes. E) explanations that support your hypothesis
C) the simplest explanation involving the smallest number of evolutionary changes.
Assume you are studying an organism in which duplications or deficiencies in the gametes are not viable. An individual is heterozygous for a pericentric inversion. A four-chromatids double crossover, with one of the two crossovers within the inversion and the other outside of it, would lead to: A) four viable gametes, two of them parental and two recombinant. B) four viable gametes, two of them with the inversion and two without. C) two viable gametes, both recombinant. D) two viable gametes, both parental. E) zero viable gametes.
C) two viable gametes, both recombinant.
A corn plant is homozygous for a mutant allele that results in no pigment in the seed (i.e., white). The mutant is caused by Ds insertion that often exits late in seed development, when there is an active Ac element in the genome. The seeds of this plant will be: A) no pigment (i.e., white). B) pigmented all over. C) white with small spots of pigment. D) white with large spots of pigment. E) weakly pigmented
C) white with small spots of pigment.
In a human population, the genotype frequencies at one locus are 0.5 AA, 0.4 Aa, and 0.1 aa. The frequency of the A allele is: A) 0.20. B) 0.32. C) 0.50. D) 0.70. E) 0.90.
D) 0.70.
Suppose that you are a genetic counselor, and a couple seeks your advice about BHT tasting (people who can taste BHT in processed food are recessive homozygotes for the "taster" allele and nontasters are homozygous dominant or heterozygous for the "nontaster" allele). Both prospective parents are nontasters, but a careful analysis of the husband's pedigree reveals that he is a carrier of the taster allele. The two alleles are in Hardy-Weinberg equilibrium, and the proportion of BHT tasters in the population is 16 percent. What is the probability that the couple's first child will be a nontaster of BHT? A) 0.0 B) 0.32 C) 0.81 D) 0.86 E) 1.0
D) 0.86
A triploid with 5 chromosomes in each set (3n = 15) is discovered. What is the probability of a meiosis in which all univalents pass to the same pole? A) 1/5 B) 1/10 C) 1/15 D) 1/16 E) 1/25
D) 1/16
What is the probability that individual "A" in the pedigree below is homozygous by descent? A) 1/8 B) 1/16 C) 1/32 D) 1/64 E) 1/256
D) 1/64
In an animal bearing the heterozygous inversion ABCDE[*]FGHI / ABGF[*]EDCHI, in one meiocyte a crossover occurred between the D and E loci and another crossover occurred between the F and G loci. The two crossovers involved all four chromatids. What will be the proportion of abnormal meiotic products from that meiosis? (Note: [*] = centromere.) A) 0% B) 25% C) 50% D) 100% E) It depends on the distance between D and E and between F and G.
D) 100%
In E. coli, the mutation of beta-lactamase in response to cefotaxime exposure involved five changes in the gene sequence, which can be accomplished through __________ different orderings. A) 16 B) 32 C) 64 D) 120 E) 240
D) 120
A hybrid allotetraploid species (2n = 60) was backcrossed to one of the suspected parents (2n = 30). When the F1 underwent meiosis, the prophase chromosome configuration was examined. If the guess about the suspected parent was correct, what would the chromosome configuration look like? A) 30 pairs B) 45 singles C) 60 singles D) 15 pairs and 15 singles E) 30 pairs and 15 singles
D) 15 pairs and 15 singles
The red fox has 17 pairs of large, long chromosomes. The arctic fox has 26 pairs of smaller shorter chromosomes. What do you expect to be the chromosome number in somatic tissues of a red fox/arctic fox hybrid? A) 13 B) 17 C) 26 D) 43
D) 43
Human albinism is an autosomal recessive trait. Suppose that you find a village in the Andes where one-fourth of the population is albino. If the population size is 1000 and the population is in Hardy-Weinberg equilibrium with respect to this trait, how many individuals are expected to be heterozygotes? A) 50 B) 250 C) 300 D) 500 E) 750
D) 500
A plant trisomic for a chromosome carrying the A gene has the genotype A/a/a. Which of the following represents a gamete this plant could NOT produce? A) A/a B) A C) a D) A/A
D) A/A
After mutagen treatment, a molecule of 2-aminopurine (an adenine analogue) incorporates into DNA. During replication, the 2-AP protonates. The mutational event caused by this will be: A) AT to CG. B) GC to AT. C) AT to TA. D) AT to GC. E) GC to CG.
D) AT to GC
Traditional" whole genome shotgun (WGS) sequencing employs which of the following techniques? A) the construction of genomic libraries B) cloning of DNA in bacterial systems C) Sanger dideoxy DNA sequencing D) All of the answer options are correct
D) All of the answer options are correct
In the diagram below, each of the five lines indicates the extent of a Drosophila deletion. A through G represent adjacent chromosomal regions (for example, in line 3 regions D and E are deleted). Regions A B C D E F G 1________ 2_______________ 3____________ 4___________ 5___________ When a radioactive DNA fragment corresponding to a Drosophila gene of interest was incubated with chromosomes carrying each of the five deletions, it bound only to chromosomes carrying deletion 1 or deletion 5. Based on this information, the gene of interest is located in region: A) A or B. B) C. C) C or D. D) D. E) E, F, or G.
D) D.
Which of the following is/are NOT a principle of Darwinian evolution? A) There is variation in morphology, physiology... B) Offspring resemble their parents... C) In any given environment... D) Darwinian evolution fully... E) All of the answer options are correct.
D) Darwinian evolution fully...
A missense mutation in Neurospora will revert by treatment with nitrous acid, but not by hydroxylamine. Hydroxylamine (HA) causes only G·C → A·T transitions, while nitrous acid causes both G·C → A·T and A·T → G·C transitions. The original mutation (not the reversion) must have been: A) AT to CG. B) AT to GC. C) AT to TA. D) GC to AT. E) GC to TA.
D) GC to AT.
Which of the following is a question that population genetics would address? A) How does cancer spread from one tissue to another? B) How does the cell copy DNA? C) How does a single nucleotide substitution cause sickle cell anemia? D) How many people have colorblindness in Utah? E) How does phenylketonuria affect brain development?
D) How many people have colorblindness in Utah?
Suppose that in Guinea pigs ABO blood types are determined like in humans, where IA and IB are expressed codominantly and i (blood type O) is recessive to both. During a set of routine crosses you notice something unusual: Repeated matings between a certain female with blood type AB and a certain male with blood type A produces F1 Guinea pigs of all four blood types in the following ratios: 5A : 2B : 4AB : 1O. The genotypes of the parents are most likely: A) IA/IB for the female and IA/IA for the male. B) IA/IB for the female and IA/i for the male. C) IA/IB/i for the female and IA/IA for the male. D) IA/IB/i for the female and IA/i for the male. E) None of the answer options are correct.
D) IA/IB/i for the female and IA/i for the male.
Which researcher proposed that change was caused by the environment acting directly on an organism, and that those changes acquired in an organism's lifetime were passed on to its offspring? A) Gould B) Darwin C) Wallace D) Lamarck E) Allison
D) Lamarck
Pyrosequencing determines the nucleotide sequence because: A) dideoxy nucleotides are incorporated into a growing DNA strand. B) dideoxy nucleotides terminate the growing DNA strand. C) PPi is incorporated into the growing DNA strand. D) PPi is released from the growing DNA strand. E) None of the answer options are correct
D) PPi is released from the growing DNA strand.
Which of the following methods can be used to inactivate a gene without changing its DNA sequence? A) targeted mutagenesis B) random mutagenesis C) gene knockout D) RNAi E) All of the answer options are correct.
D) RNAi
In E. coli, mutations arising during repair are mostly caused by: A) base excision repair. B) mismatch repair. C) recombinational repair. D) SOS repair. E) thymine dimer splitting.
D) SOS repair.
Imagine that exposure to the antibiotic streptomycin promotes mutations causing streptomycin resistance in E. coli. If you repeated Luria and Delbruck's test using streptomycin instead of the T1 phage, what results would you expect? A) None of the 20 individual cultures would show any streptomycin-resistant... B) The 20 individual cultures would show a high variation in the number.... C) The 20 individual cultures would show a high variation in the size.... D) The 20 individual cultures would show comparable numbers.... E) The 20 individual cultures would show streptomycin-resistant....
D) The 20 individual cultures would show comparable numbers...
You identify a population of mice (Peromyscus maniculatus) on an island.... ...If the climate change causes mice with black fur to die before reproducing, which of the following statements are correct? A) The B allele will disappear from the population in one generation. B) The B allele will disappear from the population in two generations. C) The fitness of mice with gray fur (WBb) must be equal to 0.5. D) The fitness of mice with black fur (WBB) is 0. E) At Hardy-Weinberg equilibrium, f(B) will equal 0.135. Answer: D
D) The fitness of mice with black fur (WBB) is 0.
A mutant plant with white flowers exists that lacks red anthocyanin pigment, normally made by enzyme P. Indeed the petal tissue lacks all detectable activity for enzyme P.. A) The mutant had another gene... B) The mutant cells likely had large scale... C) The mutant allele must have had a nonsense... D) The mutant allele must only have missense... E) None of the answers are correct.
D) The mutant allele must only have missense...
Homeosis is defined as the failure to: A) form the correct number of segments. B) correctly polarize a developing embryo. C) develop antenna. D) correctly establish segmental identity. E) None of the answer options are correct.
D) correctly establish segmental identity.
The Spo11 enzyme in eukaryotic cells makes: A) single-stranded cuts in the DNA to initiate replication. B) double-stranded cuts in the DNA to initiate replication. C) single-stranded cuts in the DNA to initiate recombination. D) double-stranded cuts in the DNA to initiate recombination. E) causes cancer.
D) double-stranded cuts in the DNA to initiate recombination.
The gene for which of the following proteins is likely to have the higher neutral rate of mutation? A) cytochrome c B) alpha subunit of hemoglobin C) beta subunit of hemoglobin D) fibrinopeptides E) actin
D) fibrinopeptides
Which of the following diagnostic features is indicative of an inversion having occurred? A) formation of chromosomal "loop" structures in meiosis I B) reduced fertility C) pseudodominance D) formation of chromosomal loops during meiosis and reduced fertility E) reduced fertility and pseudodominance
D) formation of chromosomal loops during meiosis and reduced fertility
In the developing Drosophila embryo, the Hox genes are expressed: A) in temporally restricted domains. B) uniformly throughout the embryo. C) only in homeotic mutants. D) in spatially restricted domains. E) None of the answer options are correct
D) in spatially restricted domains.
The products of the gene let-7 is a well-known: A) transcription factor. B) polarity protein. C) trans-acting activator of pair-rule genes. D) microRNA. E) homeotic protein.
D) microRNA.
A mutation changes a codon from AAA (encoding lysine) to AGA (encoding arginine) in yeast, but no mutant phenotype is detected when the mutant strain is plated and grown on minimal or complete medium. This type of mutation is called: A) synonymous. B) suppressor. C) nonsense. D) missense. E) frameshift.
D) missense.
Inbreeding in populations that are normally outbreeding leads to which of the following? A) a higher rate of genetic drift B) a higher rate of mutation C) an increase in the frequency of heterozygotes D) more individuals affected by rare diseases E) a smaller population
D) more individuals affected by rare diseases
A man is found to be karyotypically 47,XYY. The presence of an extra Y chromosome most likely results from: A) nondisjunction in a maternal meiocyte at meiosis I. B) nondisjunction in a maternal meiocyte at meiosis II. C) nondisjunction in a paternal meiocyte at meiosis I. D) nondisjunction in a paternal meiocyte at meiosis II. E) unequal crossing over.
D) nondisjunction in a paternal meiocyte at meiosis II.
In yeast, the gene phe1 is on chromosome 3 and lys4 is on chromosome 7. The progeny (spores) from the cross +; + × phe1; lys4 were: 47% +; + 44% phe1; lys4 4% phe1; + 5% +; lys4 This results suggests that: A) a nondisjunction occurred. B) one parent has a deletion. C) one parent has an inversion. D) one parent has a translocation. E) unequal crossovers occurred.
D) one parent has a translocation.
A boatload of Swedish tourists.... A) 4000 MN B) 2000 MN + 2000 MM C) 2000 MM + 2000 NN D) 2000 MN + 2000 NN E) 1000 MM + 2000 MN + 1000 NN
E) 1000 MM + 2000 MN + 1000 NN
Suppose that a population of 100 black-footed ferrets has an initial heterozygosity (H) of 0.5. How many generations will it take for this population to decline to a heterozygosity of 0.25? A) 1 B) 34 C) 68 D) 100 E) 138
E) 138
There are ______ Hox genes in the laboratory mouse. A) 12 B) 8 C) 10 D) 25 E) 39
E) 39
The genes required for proper organization of the anteroposterior body axis of the fly embryo are grouped into how many classes? A) 1 B) 2 C) 3 D) 4 E) 5
E) 5
Deducing the protein encoding genes from genomic sequences involves: A) ORF detection. B) direct evidence from cDNA sequences. C) predictions of binding site. D) predictions based on codon bias. E) All of the answer options are correct.
E) All of the answer options are correct.
If two populations of birds with frequencies of an allele a of 0.2 and 0.3 are forced together by unusually high winds, the new frequency of the a allele in the combined population will be: A) 0.2. B) 0.25. C) 0.3. D) 0.5. E) It is impossible to determine unless we know the population sizes.
E) It is impossible to determine unless we know the population sizes.
The grasses (such as barley, rice, sorghum, and corn) vary widely in the size of their genomes, yet they are descended from a common ancestor. What accounts for the variation in DNA content (i.e., the total amount of DNA)? A) large-scale duplication of genes B) large-scale loss of genes C) accumulation of LTR retrotransposons D) loss of LTR retrotransposons E) None of the answer options are correct.
E) None of the answer options are correct.
Which of the following is/are TRUE about pyrosequencing? A) Pyrosequencing uses ddNTPs as substrates. B) Pyrosequencing uses DNA polymerase and two other enzymes, sulfurylase and luciferase, in the reaction. C) PPi is released for every nucleotide incorporated into the growing strand. D) All of the answer options are correct. E) Pyrosequencing uses DNA polymerase, sulfurylase, and luciferase, and PPi is released for every nucleotide incorporated into the growing strand.
E) Pyrosequencing uses DNA polymerase, sulfurylase, and luciferase, and PPi is released for every nucleotide incorporated into the growing strand.
Which of the following statements is/are TRUE about reverse genetics? A) Reverse genetics analysis starts with an altered phenotype in an organism. B) Reverse genetics analysis starts with a known DNA sequence, mRNA, or protein. C) Reverse genetics can be performed by random mutagenesis, targeted mutagenesis,or by phenocopying. D) All of the answer options are correct. E) Reverse genetics analysis starts with a known DNA sequence, mRNA, or protein, and it can be performed by random mutagenesis, targeted mutagenesis, or by phenocopying.
E) Reverse genetics analysis starts with a known DNA sequence, mRNA, or protein, and it can be performed by random mutagenesis, targeted mutagenesis, or by phenocopying.
The best evidence to prove that a candidate gene is a disease gene is finding: A) a start and stop codon. B) a CpG island upstream. C) that the gene is expressed. D) the homologous gene in many similar animals. E) a mutation in the homologous sequence from a disease sufferer
E) a mutation in the homologous sequence from a disease sufferer
People who develop the hereditary form of retinoblastoma inherit: A) a pair of dominant alleles causing retinoblastoma. B) a pair of normal (non-retinoblastoma) alleles. C) a pair of recessive alleles causing retinoblastoma. D) a single dominant allele causing retinoblastoma. E) a single recessive allele causing retinoblastoma.
E) a single recessive allele causing retinoblastoma.
Mice that are homozygous for a complete deletion of the wild-type gene "T" develop multiple tumors in a variety of tissues very early in life. Gene "T" is most likely: A) an activated oncogene. B) a dominant tumor suppressor gene. C) an oncogene. D) a proto-oncogene. E) a tumor suppressor gene.
E) a tumor suppressor gene.
The melanocortin 1 receptor protein displays four amino acid substitutions between dark- and light-colored populations of pocket mice. In dark mice, these unique amino acids cause the receptor to: A) fold inappropriately in the cell membrane. B) incorrectly identify ligand. C) be non-functional in regulating gene expression. D) be internalized and degraded. E) be constitutively active.
E) be constitutively active.
Organophosphate resistance in the sheep blowfly (Luciliacuprina) is an example of: A) the toxicity of insecticides. B) the generation of neutral mutations over time. C) a lethal frameshift mutation. D) cumulative selection. E) evolutionary selection of a single amino acid change in a protein.
E) evolutionary selection of a single amino acid change in a protein.
A small (one base pair) insertion in the middle of the coding region of a gene will cause a: A) synonymous mutation. B) silent mutation. C) nonsense mutation. D) missense mutation. E) frameshift mutation.
E) frameshift mutation.
A population is currently in Hardy-Weinberg equilibrium with respect to the A locus. If (positive) assortative mating occurs for one generation, the expected outcome is an increase in the frequency of the: A) A allele. B) a allele. C) A- phenotype. D) heterozygous genotype (A/a). E) homozygous genotypes (A/A and a/a).
E) homozygous genotypes (A/A and a/a).
Which of the following processes will increase variation between populations? A) earthquakes B) mutation C) migration D) balancing selection E) inbreeding
E) inbreeding
The two loci Y (y) and R (r) are normally 20 map units apart. A particular dihybrid individual is heterozygous for an inversion that spans 98% of the region between Y and R, but does not include Y or R. If this dihybrid is testcrossed to an individual with normal chromosomes, the recombinant frequency in progeny will be: A) more than 20%. B) 20%. C) less than 20%, but more than 10%. D) 10%. E) less than 10%.
E) less than 10%.
IS-induced mutations are different from missense mutations in that they are: A) nonrevertible. B) less severe. C) more severe. D) nonpolar. E) not reverted by mutagens.
E) not reverted by mutagens
Which of the following is the most sensible order of techniques for mapping a chromosome and then locating a specific disease gene? A) contig alignment; restriction mapping; RFLP linkage analysis; chromosomal walking B) chromosomal walking; contig alignment; restriction mapping; RFLP linkage analysis C) restriction mapping; chromosomal walking; contig alignment; RFLP linkage analysis D) chromosomal walking; restriction mapping; RFLP linkage analysis; contig alignment E) restriction mapping; contig alignment; RFLP linkage analysis; chromosomal walking
E) restriction mapping; contig alignment; RFLP linkage analysis; chromosomal walking
In Neurospora, the genes his2 and leu2 are closely linked. From a cross, his2 × leu2, which is a rare octad of the following type, arose: This octad most likely arose by: A) crossover between his2 and leu2, followed by first-division nondisjunction. B) first-division nondisjunction. C) post-meiotic mitotic nondisjunction. D) rare triploidy. E) second-division nondisjunction.
E) second-division nondisjunction.
Inherited blindness in some cavefish arose through: A) an individual mutant fish that displayed reproductive success. B) atrophy of the eye when unused in darkness. C) viral infection of the optic nerve. D) a defect in gene splicing. E) separate incidences of inactivating mutation in the Oca2 gene.
E) separate incidences of inactivating mutation in the Oca2 gene.
Retrotransposons move via an intermediate that is: A) a double-stranded lollipop. B) a retrovirus. C) double-stranded RNA. D) single-stranded DNA. E) single-stranded RNA.
E) single-stranded RNA.
The term coverage, when applied to genomics, means sequencing: A) every base pair of the entire genome. B) every base pair of a single chromosome. C) the same gene in multiple individuals. D) the same gene in multiple species. E) the same base pair multiple times.
E) the same base pair multiple times.
Tony Allison examined the allele frequency of hemoglobin (HbA, or HbS) in populations of Kenyon tribes. A surprising result of this study was that: A) the HbS and HbA alleles were evenly distributed among Kenyan tribes. B) the HbS alleles appeared more frequently in men than in women. C) tribes living in arid or highland regions had high frequencies of HbS alleles. D) tribes living near Lake Victoria had a low frequency of HbS alleles. E) tribes living in arid or highland regions had low frequencies of HbS alleles.
E) tribes living in arid or highland regions had low frequencies of HbS alleles.
Fragile X syndrome is caused by: A) exposure to high doses of 5-bromouracil. B) exposure to high doses of free radicals. C) an inherited microdeletion. D) spontaneous depurination. E) trinucleotide expansion.
E) trinucleotide expansion.
What group of organisms has, overall, the highest genetic diversity? A) humans B) invertebrates C) plants D) vertebrates other than humans E) unicellular eukaryotes
E) unicellular eukaryotes
Assume you are studying an organism in which duplications or deficiencies in the gametes are not viable. An individual is heterozygous for a paracentric inversion. A four-chromatids double crossover, with one of the two crossovers within the inversion and the other outside of it, would lead to: A) four viable gametes, two of them parental and two recombinant. B) four viable gametes, two of them with the inversion and two without. C) two viable gametes, both recombinant. D) two viable gametes, both parental. E) zero viable gametes.
E) zero viable gametes.
Assume you are studying an organism in which duplications or deficiencies in the gametes are not viable. An individual is heterozygous for a pericentric inversion. A four-chromatids double crossover, with both crossovers occurring within the inversion, would lead to: A) four viable gametes, two of them parental and two recombinant. B) four viable gametes, two of them with the inversion and two without. C) two viable gametes, both recombinant. D) two viable gametes, both parental. E) zero viable gametes.
E) zero viable gametes.
