Mid Term - Bios2410 Genetic Exam
1. Sexual ___________ is the complex set of responses by cells, tissues, and organs to those genetic signals 2. In sexual ________________ , genes signal developmental pathways whereby the sexes are generated. Differentiation, Determination
1. differentiation 2. determination
A horse has 2n = 64, whereas a donkey has 2n = 62. How many chromosomes does a mule (the offspring of a horse×donkey cross) have? A. 2n = 64 B. 2n = 62 C. 2n = 63 D. 2n = 126 E. 2n = either 64 or 62, depending on which organism was the mother
C. 2n = 63
The most plausible explanation for why more human males are conceived than females is that ___________. A. males produce more Y-bearing sperm than X-bearing sperm B. Y-bearing sperm are more viable than X-bearing sperm C. Y-bearing sperm are more motile than X-bearing sperm D. the female reproductive tract is less hospitable to X-bearing sperm E. the egg is more receptive to Y-bearing sperm
C. Y-bearing sperm are more motile than X-bearing sperm
When strains A and B (auxotrophic for different compounds) are mixed together, they readily form prototrophs; however, in the Davis U tube, they do not. These cells are most likely undergoing ___________. A. transduction B. transformation C. conjugation D. mutation E. lysogeny
C. conjugation
If two loci cotransform frequently, ___________. A. they are both on the same plasmid B. they are both carried by the same phage DNA molecule C. they are closely linked D. they are on the same chromosome but more than 50 map units apart E. they are unlinked
C. they are closely linked
If a species has diploid number of 10, but gave rise to progeny with 20 chromosomes, what term would we use to describe the progeny? tetraploid diploid triploid aneuploid haploid
tetraploid
If two genes on the same chromosome exhibit complete linkage, what is the expected F2 phenotypic ratio from a selfed heterozygote with the genotype a + b + ⁄⁄ ab? 1:1:1:1 3:1 9:3:3:1 1:1
3:1
Klinefelter syndrome in humans, which leads to underdeveloped testes and sterility, is caused by which chromosomal condition? triploidy 47 , XYY 45 , X 47 , XXY 47 , 21+
47 , XXY
Which of the following causes cri-du-chat syndrome? A. Deletion B. Duplication C. Insertion D. Nonreciprocal translocation E. Reciprocal translocation
A. Deletion
A human individual with 45 chromosomes has a ________. A. monosomy B. trisomy C. monoploidy D. diploidy E. triploid
A. monosomy
Jill is heterozygous for gene A and is going to have a child with Jack, who is homozygous recessive for gene A. Which of the following offspring genotypes could result from the fertilization of an egg that had undergone nondisjunction in meiosis I with a normal haploid sperm? AAa Aaa aaa Aa aa a
Aaa a
Now, suppose that the three tomato genes from Part A did not assort independently, but instead were linked to one another on the same chromosome. Would you expect the phenotypic ratio in the offspring to change? If so, how? Which statement best predicts the results of the cross MmDdPp x mmddpp assuming that all three genes are linked? Only the parental phenotypes could possibly occur in the offspring. Lack of independent assortment means that you cannot predict the frequencies of phenotypes in the offspring. All eight possible phenotypes would occur in equal numbers in the offspring (1:1:1:1:1:1:1:1). All eight possible phenotypes could occur, but a greater proportion of the offspring would have the parental phenotypes.
All eight possible phenotypes could occur, but a greater proportion of the offspring would have the parental phenotypes.
The genes ABC occur in that order in fruit flies. A is 10 map units from B, and B is 20 map units from C. What is the expected frequency of double crossovers? A. .02 % B. 2% C. 10% D. 20% E. 30%
B. 2%
The genes ABC occur in that order in fruit flies. A is 10 map units from B, and B is 20 map units from C. How far is A from C? A. 0.2 map units B. 10 map units C. 20 map units D. 30 map units E. 40 map units
D. 30 map units
Linkage affects expected ratios because it violates which of Mendel's postulates? A. There are two alleles for a gene in diploid organisms. B. Alleles undergo segregation at meiosis. C. Alleles have dominant/recessive relationships. D. Homologs independently assort in meiosis. E. Linkage does not affect ratios.
D. Homologs independently assort in meiosis.
How many chromosomes would be found in an allopolyploid plant if its parents had diploid numbers of 4 and 6 respectively? Diploid number of 10 Haploid number of 12 Diploid number of 5 Haploid number of 5
Diploid number of 5
The genes ABC occur in that order in fruit flies. A is 10 map units from B, and B is 20 map units from C. You test cross a triply heterozygous fly and score 1000 offspring. You observe 6 flies with double crossover phenotype. What is I? A. 6 B. .6 C. .06 D. 0.2 E. 0.7
E. 0.7
This image shows the result of a serial dilution and culturing of a bacterial sample. The plate shown has 1 ml of a dilution. What is the concentration of cells in the original culture? A. 12 cells ml B. 120 cells ml C. 12x10^-6 cells/ml D. 1.2x10^6 cells/ml E. 12x10^6 cells/ml
E. 12x10^6 cells/ml
In the following cross of the X-linked, recessive traits yellow body, white eye, and echinus, if a double-crossover occurred in the female parent, what would be the phenotype(s) of the resultant offspring? A. All wild-type or all mutant flies of either sex B. Wild-type females and triply mutant males C. All females wild-type and 1:1 white eyes males:yellow body and echinus males D. 1:1 white eyes and yellow body females:echinus females, and all wild-type males E. 1:1 white eyes flies:yellow body and echinus flies, could be either sex
E. 1:1 white eyes flies:yellow body and echinus flies, could be either sex
An interrupted mating experiment was performed with three strains of Hfr E. coli bacteria. Based on these three results, draw a map of the genes. A. AKWVZD B. KADZVW C. ZDAKWV D. VWKADZ E. All of the above are correct.
E. All of the above are correct. Because the E. coli chromosome is circular
The following structure observed during prophase 1 could be due to _________. Extra DNA material, DNA Loop A. pericentric inversion B. duplication C. deletion D. insertion E. deletion or insertion
E. deletion or insertion
Harlequin chromosomes are a demonstration of ____________. A. double crossovers B. three-strand double exchange C. gene conversion D. mitotic recombination E. sister chromatid exchange
E. sister chromatid exchange
Fragile-X syndrome is caused by which of the following genes? SRGAP2 DSCR1 CCL3L1 EGFR FMR1
FMR1
A cross between a tetraploid and a diploid member of the same species will produce offspring that can undergo sexual reproduction. True False
False
Crossing over during prophase I of meiosis occurs between alleles on sister chromatids True False
False
In most species, males produce unlike gametes that determine the gender of their offspring and are, therefore, known as the homogametic sex.In most species, males produce unlike gametes that determine the gender of their offspring and are, therefore, known as the homogametic sex. True False
False
Why is a 50 percent recovery of single-crossover products the upper limit, even when crossing over always occurs between two linked genes? 1. Because crossing over occurs at the _____________ of the cell cycle, notice that each single crossover involves only _______________ of the ___________ chromatids. Four Strand Stage Six Strand Stage Eight Strand Stage Two Strand Stage Two Three Four One Six Eight
Four Strand Stage Two and Four
The XYY condition in humans is caused by nondisjunction in _______? Males in meiosis I Males in meiosis II Male in Meiosis I or II females in meiosis I females in meiosis II
Males in meiosis II
Which of the following characteristics is comon to species that reproduce sexually? Morphologically distinguishable male and female gametes The diploid adult stage Different sets of sex chromosomes in males and females The Y Chromosome in males Meiosis
Meiosis
If Jack and Jill have a child with an Aaa genotype, during which meiotic division, and in which parent, could nondisjunction have occurred? Meiosis I in the mother Meiosis II in the mother Meiosis I in the father Meiosis II in the father
Meiosis I in the mother Meiosis I in the father Meiosis II in the father
If Jack and Jill have a child with an AAa genotype, during which meiotic division, and in which parent, could nondisjunction have occurred? Meiosis I in the mother Meiosis II in the mother Meiosis I in the father Meiosis II in the father
Meiosis II in the mother
If Jack and Jill have a child with an aaa genotype, during which meiotic division, and in which parent, could nondisjunction have occurred? Meiosis I in the mother Meiosis II in the mother Meiosis I in the father Meiosis II in the father
Meiosis II in the mother Meiosis I in the father Meiosis II in the father
In Chickens, the hens are the heterogametic sex. Which sex has the Y chromosome. Males Females Both Only Heterozygous females Neither male nor female
Neither male nor female
Which of the following elements allows for homologous pairing in meiosis? Xic PARS MSY Xist SRY
PARS
Which of the following statements about gamete formation during meiosis is false? Recombinant gametes contain combinations of alleles not found in the parent cell. Parental gametes contain the same combinations of linked genes as found in the parent cell. Complete linkage results in the formation of only parental gametes. Parental gametes can be formed only if there is no crossing over during meiosis.
Parental gametes can be formed only if there is no crossing over during meiosis.
Which of the following elements is responsible for determining male sex in humans? SRY Xist Xic PARS MSY
SRY
Sam is male horse. When a karyotype is done on him, he is observed to have two x chromosomes and no Y chromosome. What is the most likely explanation? Nondisjunction in his mother Nondisjunction in his father Nondisjunction in either parent The SRY region must have translocated to the X chromosome Horses do not use the X-Y system, but the Z-W
The SRY region must have translocated to the X chromosome
In Drosophila, sex is determined by a balance between the number of haploid sets of autosomes and the number of ________. X chromosomes centromeres Y chromosomes satellite chromosomes chromomeres
X chromosomes
A young boy is diagnosed with hemophilia A, a recessive, X-linked condition. If neither parent has hemophilia A, what are their genotypes? XA Xa , XA Y XA XA, Xa Y Xa Xa , XA YA Mother be either XA XA or XA Xa, but father is Xa Y Cannot predict from the information given
XA Xa , XA Y
In humans, the genetic basis for determining the sex "male" is accomplished by the presence of ________. high levels of estrogen multiple alleles scattered throughout the autosomes a balance between the number of X chromosomes and the number of haploid sets of autosomes a portion of the Y chromosome one X chromosome
a portion of the Y chromosome
Cri-du-chat syndrome is due to __________ in the short arm of chromosome 5. a duplication a segmental deletion an inversion a translocation
a segmental deletion
What term most specifically describes when a polyploid organism contains an equivalent of four haploid genomes derived from separate species? tetraploidy allotetraploidy euploidy autotetraploidy aneuploidy
allotetraploidy
Which of the following is a method for harvesting fetal cells for karyotyping? chorionic villus sampling amniocentesis, chorionic villus sampling, and noninvasive prenatal genetic diagnosis noninvasive prenatal genetic diagnosis amniocentesis fetal ultrasound
amniocentesis, chorionic villus sampling, and noninvasive prenatal genetic diagnosis
The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as ________. polyploidy trisomy euploidy triploidy aneuploidy
aneuploidy
Nondisjunction in the first meiotic division in a human male could result at fertilization in ______ ? the XYY condition Turner Syndrome Klinefelter Syndrome XXX Syndrome either B or C
either B (Turner Syndrome) or C (Klinefelter Syndrome)
The condition that exists where complete haploid sets of chromosomes are present is known as ________. polyploidy triploidy euploidy diploidy aneuploidy
euploidy
Klinefelter syndrome (47, XXY) and Turner syndrome (45, X) are due to __________. improper segregation of autosomes during meiosis improper segregation of sex chromosomes during meiosis improper segregation of autosomes during mitosis improper segregation of sex chromosomes during mitosis
improper segregation of sex chromosomes during meiosis
When two genes fail to assort independently, the term normally applied is ________. tetrad analysis dominance and/or recessiveness Mendelian inheritance linkage discontinuous inheritance
linkage
A genomic condition that may be responsible for some forms of fragile-X syndrome, as well as Huntington disease, involves ________. multiple inversions in the X chromosome multiple breakpoints fairly evenly dispersed along the X chromosome various lengths of trinucleotide repeats plasmids inserted into the FMR-1 gene single translocations in the X chromosome
various lengths of trinucleotide repeats
In a cross between these two plants (MMDDPP x mmddpp), all offspring in the F1 generation are wild type and heterozygous for all three traits (MmDdPp). Now suppose you perform a testcross on one of the F1 plants (MmDdPp x mmddpp). The F2 generation can include plants with these eight possible phenotypes: solid, normal, smooth solid, normal, peach solid, dwarf, smooth solid, dwarf, peach mottled, normal, smooth mottled, normal, peach mottled, dwarf, smooth mottled, dwarf, peach Assuming that the three genes undergo independent assortment, predict the phenotypic ratio of the offspring in the F2 generation. 27 : 9 : 9 : 9 : 3: 3 : 3 : 1 1 : 0 : 0 : 0 : 0 : 0 : 0 : 0 1 : 0 : 1 : 0 : 1 : 0 : 1 : 0 1 : 1 : 1 : 1 : 1 : 1 : 1 : 1
1 : 1 : 1 : 1 : 1 : 1 : 1 : 1
For linked genes A, B, and C, the map distance A-B is 5 map units and the map distance B-C is 25 map units. If there are 10 double crossover events out of 1000 offspring, what is the interference? 0.0125 0.2 0.8 0.01
0.2 The coefficient of coincidence is 0.01/0.0125 = 0.8, so the interference is 1 - 0.8 = 0.2.
In a three‑point mapping experiment for the genes y‑w‑ec, the following percentages of events are observed: NCO events: 65%; SCO events between y and w: 15%; SCO events between y and ec: 17%; DCO events: 3% What is the map distance between y and ec? 17 Map Units 18 Map Units 20 Map Units 15 Map Units
20 Map Units
The sex of birds, some insects, and other organisms is determined by a ZW chromosomal arrangement in which the males have like sex chromosomes (ZZ) and females are ZW (similar to XY in humans). Assume that a recessive lethal allele on the Z chromosome causes death of an embryo in birds. What sex ratio would result in the offspring if a cross were made between a male heterozygous for the lethal allele and a normal female? 2:1 male to female 4:1 male to female 1:1 male to female 3:1 male to female 1:2 male to female
2:1 male to female
Drosophila, like humans, have X and Y chromosomes. However, unlike humans, it is the ratio of the number of X chromosomes to sets of autosomes that determines the sex of the fly. A fly has one X chromosome, and two sets of autosomes (a diploid set), but no Y. What is its sex? A. Male B. Female C. Intersex D. Metamale E. Metafemale
A. Male
Escherichia coli O157:H7 can cause serious foodborne illness. This strain of E. coli has acquired the ability to create a toxin normally produced in the bacterial species Shigella. Which of the following would not explain this ability found in E. coli? A. Vertical transfer B. Horizontal transfer C. Recombination D. Transformation
A. Vertical transfer
Three genes on the Drosophila X chromosome are examined pairwise. It is determined that they have the following recombination rates: (1) yellow, white 0.5 percent (2) white, miniature 34.5 percent (3) yellow, miniature 35.4 percent Which two genes are physically closest together? A. Yellow and white B. White and miniature C. Yellow and miniature D. All three are about equally spaced. E. One cannot tell from this information.
A. Yellow and white
Two genes that are 60 map units apart are expected to show __________. A. independent assortment B. 25 percent recombination C. 30 percent recombination D. 50 percent recombination E. 60 percent recombination
A. independent assortment
Which of the following offspring genotypes could result from the fertilization of an egg that had undergone nondisjunction in meiosis II with a normal haploid sperm? AAa Aaa aaa Aa aa a
AAa aaa Aa aa a
Nondisjunction in meiosis 1 results in _______ .Nondisjunction in meiosis 1 results in ___________. A. 2 normal gametes and 2 abnormal gametes B. 2 gametes that are n+1 and 2 gametes that are n-1 C. 4 normal gametes D. normal chromosome complements in meiosis 2 cells, but abnormal after completion of meiosis E. nondisjunction in meiosis 2 also
B. 2 gametes that are n+1 and 2 gametes that are n-1
Genes L and M are 10 map units apart. You cross a homozygous LLMM with an llmm and then testcross the F1 . If there are 100 offspring, how many are Llmm? A. 0 B. 5 C. 25 D. 45 E. 50
B. 5
A man with Klinefelter's syndrome has normal color vision. His mother was color-blind, but his father had normal color vision. From this information, can you determine which parent underwent nondisjunction? A. Mother B. Father C. Either could have undergone nondisjunction to end up with this result D. Neither, as Klinefelter's is not due to nondisjunction E. Not enough information to make a determination
B. Father
A karyotype is done on a phenotypically female patient, and it is discovered that she has a Y chromosome. However, the Y chromosome appears to have a deletion. What region is most likely deleted? A. PAR B. SRY C. Centromere D. MSY E. Heterochromatin of MSY
B. SRY
Can a person have 45 chromosomes and be phenotypically normal? A. Yes; this happens often. B. Yes, if the person is a translocation carrier. C. Yes, if it is the X chromosome that is monosomic. D. No; not having 46 chromosomes will always result in some abnormal phenotype. E. No; having only 45 chromosomes is lethal in humans.
B. Yes, if the person is a translocation carrier.
In an Hfr x F- mating, if the order of transfer of loci is leu - azi - ton- lac, one can conclude that ______________ A. leu is adjacent to lac B. leu is adjacent to the point of origin C. the next transferred locus will be gal D. there are five time units between azi and ton E. all of the above are true
B. leu is adjacent to the point of origin
When live Streptococcus pneumoniae cells from rough colonies are mixed with dead Streptococcus pneumoniae cells from smooth colonies, frequently, smooth colonies can be isolated. This is most likely due to _____________. A. conjugation B. transformation C. transduction D. vertical transfer E. experimental error
B. transformation
What is the unit of distance between genes based on a physical map? Lod scores Map units base pairs inches centiMorgans
Base Pairs
Which of the following best describes the Lyon hypothesis? A. Barr bodies are inactivated X chromosomes. B. The paternal X chromosome of a female is inactivated in an early embryonic stage. C. The maternal X chromosome of a female is inactivated in an early embryonic stage. D. One of the two female X chromosomes is randomly inactivated in an early embryonic stage. E. Each cell of a female randomly inactivates one X chromosome shortly after mitosis.
D. One of the two female X chromosomes is randomly inactivated in an early embryonic stage.
What do transformation, transduction, and conjugation all have in common? A. They all require a pilus. B. They all require a viral helper. C. They all use plasmids. D. They all involve the exchange of DNA between different bacteria. E. They all only work on bacteria within the same species.
D. They all involve the exchange of DNA between different bacteria.
An amphidiploid is a type of ___________ and is usually ___________. A. autopolyploid; sterile B. autopolyploid; fertile C. allodiploid; sterile D. allotetraploid; fertile E. chromosomal abnormality; sterile
D. allotetraploid; fertile
Fragile sites ___________. A. are always associated with a phenotypic disorder B. are limited to the X chromosome C. have been implicated in most forms of cancer D. are often associated with regions of short tandem DNA sequence repeats E. all of the above
D. are often associated with regions of short tandem DNA sequence repeats.
The amino acid tryptophan is abbreviated "trp." An E. coli trp auxotroph can grow on __________. A. minimal medium B. minimal medium plus amino acids C. complete medium D. both B and C E. A, B, and C
D. both B and C
The phenotypic classes of offspring representing double crossovers ___________. A. occur in a frequency that is the product of the single-crossover frequencies B. occur in a frequency that is less than the product of the singlecrossover frequencies C. occur in a frequency that is greater than the product of the single-crossover frequencies D. occur less frequently than single-crossover classes E. occur more frequently than single-crossover classes
D. occur less frequently than single-crossover classes
Methods for determining the linkage group and genetic map in humans involve ________. DNA Markers dihybrid test crosses tetrad analysis and bromodeoxyuridine gamete genotyping twin spots and tetrad analysis
DNA Markers
Which of the following statements about Down syndrome is false? A. Individuals with Down syndrome are triploid. B. Down syndrome occurs due to nondisjunction in either meiotic division, but only in the mother. C. Most Down syndrome births happen to women over age of 35 years. D. Familial Down syndrome is due to nondisjunction. E. All of the above are false
E. All of the above are false
Which of these may be due to unequal crossing over? A. Deletion B. Duplication C. Insertion D. Nonreciprocal translocation E. Both deletions and duplications may be due to unequal crossing over
E. Both deletions and duplications may be due to unequal crossing over
Genes K and D are 6 map units apart. What does that mean? A. That 6 percent of the time both genes are homozygous. B. That 6 percent of the time both genes are heterozygous. C. That they are 6 kb apart on the chromosome (1 kb = 1000 base pairs) D. That they are completely linked 6 percent of the time E. That recombination (crossing over) occurs 6 percent of the time between these two genes
E. That recombination (crossing over) occurs 6 percent of the time between these two genes
Autotriploids ________________. A. may result from the fertilization of a haploid gamete with an abnormal diploid gamete B. may result from the fertilization of an egg by two haploid sperm C. may result from the crossing of a diploid with a tetraploid D. have three chromosome sets that are identical in terms of number and content E. all of the above
E. all of the above
To construct a mapping cross of linked genes, it is important that the genotypes of some of the gametes produced by the heterozygote can be deduced by examining the phenotypes of the progeny. True False
False
Which statement best describes human sex determination? Females are heterogametic Individuals with a Y chromosome are male. Individuals with a two X chromosomes are female. Individuals with at least twice as many X chromosomes as Y chromosomes are female. Individuals with one X chromosome are male.
Individuals with a Y chromosome are male.
Which of the following statements about nondisjunction is FALSE? It only occurs during meiosis I. It occurs more frequently in human females over age 35. It may fail to separate maternal from paternal chromosomes. It may fail to separate maternal chromatids from one another or paternal chromatids from one another.
It only occurs during meiosis I.
Which of the following has one Barr body? Triplo-X female Turner's Klinefelter's and normal female Normal female Klinefelter's
Klinefelter's and normal female
Why do human monosomics most often fail to survive prenatal development? Lethal alleles that were previously masked by their wild-type counterparts are now expressed. Monosomy can result in insufficient levels of certain required gene products, leading to death. In monosomics, larger chromosomes, that cause greater genetic imbalance than smaller ones, are formed. A full diploid set of chromosomes is required to proceed the fetus to birth. Due to the absence of a homologous chromosome, unequal crossing over takes place.
Lethal alleles that were previously masked by their wild-type counterparts are now expressed. Monosomy can result in insufficient levels of certain required gene products, leading to death.
Interpret these data as they relate to the effect of temperature on sex determination. Lizards appear to have their sex determined by factors other than temperature in the 20-40∘C∘C range. In snapping turtles, sex determination is strongly influenced by temperatures, but there is no range of temperature that favors females. Lizards have no factors that influence their sex determination. In snapping turtles, sex determination is strongly influenced by temperatures such that females are favored in the 26-34∘C∘C range. In snapping turtles, sex determination is strongly influenced by temperatures such that males are favored in the 26-34∘C∘C range.
Lizards appear to have their sex determined by factors other than temperature in the 20-40∘C∘C range. In snapping turtles, sex determination is strongly influenced by temperatures such that males are favored in the 26-34∘C∘C range.
Which genetic disease is caused by a trisomy for chromosome 13? Down syndrome Patau syndrome Klinefelter syndrome Edwards syndrome
Patau syndrome
How do sex chromosomes contrast with autosomes? (Select 3) Sex chromosomes carry genes responsible for the development of male or female gonads. In some species, the lack of sex chromosomes (one or both) is not lethal to the organism. Compensation mechanisms exist for having extra autosomes, but not extra sex chromosomes. In a diploid organism, one member of the sex chromosome pair may be inactivated without significant consequences. Sex chromosomes carry genes coding for the synthesis of sex hormones. In a diploid organism, sex chromosomes are represented by homomorphic pairs in both sexes.
Sex chromosomes carry genes responsible for the development of male or female gonads. In some species, the lack of sex chromosomes (one or both) is not lethal to the organism. In a diploid organism, one member of the sex chromosome pair may be inactivated without significant consequences.
Which of the following is/are true of generalized bacteriophage transduction? The bacteriophage chromosome has a region homologous to the bacterial chromosome. The bacteriophage packages fragments of bacterial DNA into new phage particles. The bacteriophage must enter the lysogenic cycle. Submit
The bacteriophage packages fragments of bacterial DNA into new phage particles.
Which of the following statements about Barr bodies is true? The formation of Barr bodies ensures that males and females have equal doses of genes on the X chromosome. They contain no DNA. They are visible only in males. They are inactivated Y chromosomes.
The formation of Barr bodies ensures that males and females have equal doses of genes on the X chromosome.
What are pseudoautosomal regions (PARs) on the sex chromosomes? They are homozygous regions of autosomal chromosomes. They are hemizygous regions of the X and Y chromosomes. They are regions of the X and Y chromosomes that do not recombine during meiosis. They are homologous regions of the X and Y chromosomes.
They are homologous regions of the X and Y chromosomes.
Which of the following statements about allopolyploid individuals is true? They may be sterile and unable to produce offspring. They can be formed when two sperm simultaneously fertilize an ovum within the same species. They are generated from exposure to colchicine. They result from a mating between individuals of the same species.
They may be sterile and unable to produce offspring.
Although the vast majority of women who inherit a single copy of an X-linked recessive disease allele are not affected by the disorder, a small percentage of women do display the disease phenotype. Which of the following could explain this rare phenomenon? Turner syndrome (a sex-chromosome aneuploidy in which women have only one X chromosome) X-inactivation that favors inactivation of the normal X chromosome multiple alleles of the X-linked recessive trait incomplete penetrance of the X-linked recessive allele
Turner syndrome (a sex-chromosome aneuploidy in which women have only one X chromosome) X-inactivation that favors inactivation of the normal X chromosome
Which of the following is an example of a translocation? There is an occurrence of nondisjunction at meiosis I. There is an occurrence of nondisjunction at meiosis II. Two chromosomes have experienced breaks at their terminal ends (e.g., chromosome 6 and 18), and during the rejoining process, the ends get switched. The end of chromosome 6 becomes attached to chromosome 18 and vice versa. A chromosome contains the mutant sickle cell allele.
Two chromosomes have experienced breaks at their terminal ends (e.g., chromosome 6 and 18), and during the rejoining process, the ends get switched. The end of chromosome 6 becomes attached to chromosome 18 and vice versa.
Which protein is responsible for converting androgens into estrogens? testis determining factor sex lethal aromatase doublesex transformer
aromatase
What term is used when two known diploid species fertilize to create a tetraploid offspring? autopolyploidy amphidiploidy euploidy tetraploidy allopolyploidy
amphidiploidy
Consider the following cross: Gl/gL x gl/gl Which combination(s) of alleles does the parent with the gl/gl genotype contribute to the offspring? gL Gl GL gl
gl
Consider the following cross: Gl/gL x gl/gl Which combination(s) of alleles does the parent with the Gl/gL genotype contribute to the offspring? gl Gl gL GL
gl Gl gL GL
If a species has a haploid number of 10, what term would we use to describe an individual with 11 chromosomes? triploid monosomic trisomic haploid eusomic
trisomic
What distinguishes paracentric inversions from pericentric inversions? whether or not a centromere is included in the inversion the formation of an inversion loop one suppresses crossovers, and the other encourages crossovers the number of viable gametes formed
whether or not a centromere is included in the inversion
