BI 311 Genetics Weeks 6-8

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Assume that the autotriploid cell in the image has 3𝑛=30 chromosomes. For each of the gametes produced by this cell, what would the chromosome number of the resulting zygote be if the gamete fused with a normal haploid gamete?

30 20 20 30 40 10

Cystic Fibrosis is an autosomal recessive disease. It affects 1 of 2500 people in a population in H-W equilibrium. Estimate the frequency of heterozygous carriers f(Aa).

What percentage (%) of the total plaques will be represented by the plaque type b+ t+ ?

44% (88/2)

A human monosomic zygote, trisomic zygote, and nullisomic zygote has ______chromosomes respectively?

45, 47, 44

Species I (AABBCC, 2n=6) and Species II (GGHHII, 2n=6) both produce haploid gametes. Gametes from species I and II were fused and a hybrid was created. How many chromosomes does the hybrid have?

In a cross between the two phage strains: hr+ and h+r , 92% of the progeny display parental phenotypes. What is the genetic map distance between the gene markers h and r?

8 mu

Species I (AABBCC, 2n=6) and Species II (GGHHII, 2n=6) both produce haploid gametes. Gametes from species I and II were fused and a hybrid was created. What is the genotype of this hybrid?

ABCGHI

If aneuploidy negatively interferes with normal development of organisms, why would fetuses with extra copies of small autosomes be able to occasionally complete development?

Because small chromosomes carry relatively few genes, so presence of extra copies of small chromosomes is less detrimental than extra copies of larger chromosomes

The diagram shows the relative activity of a proto oncogene and a tumor supressor gene in a normal cell, as well as the activity in four other cells. Which of these cells would be expected to be cancer cells?

Cells B and C

What term describes the transfer of genetic material between bacteria through cell-to-cell contact?

Conjugation

Conjugation between what two types of auxotrophic strains could result in recombinant cells that can grow on a minimal medium lacking in methionine and threonine?

Conjugation between and Hfr strain (met+the) and an F- strain (met the+)

DNA damage can occur as a result of exposure to chemicals or ultraviolet radiation. What happens during nucleotide excision repair of damaged DNA?

Enzymes open the DNA strand, remove a segment of DNA from the strand that contains the damage, and resynthesize the correct DNA sequence.

Indicate the types of matings that are possible. Select the THREE correct answers.

F' × F- F+ × F- Hfr × F-

Match each characteristic to the proper bacterial fertility factor type.

F- bacterium does not contain the F factor sequences recipient of DNA during bacterial conjugation F+ bacterium contains a plasmid with only the F factor F' bacterium contains a plasmid with the F factor and some genomic DNA Hfr bacterium bacteria with F factor integrated into genome

TRUE or FALSE? Sickle-cell anemia in humans is an autosomal recessive trait that results from a mutation in a gene that codes for hemoglobin. Heterozygotes contain enough normal hemoglobin to prevent sickle-cell anemia. Moreover, such heterozygotes are resistant to malaria.Natural selection tends to favor the sickle cell allele where malaria is NOT prevalent.

FALSE

True or False. Inbreeding leads to H-W equilibrium frequencies of p^2, 2pq, and q^2.

FALSE

TRUE or FALSE Horizontal gene transfer may play a role in the evolution of prokaryotes (e.g., in the spread of bacterial antibiotic resistance), but does not play a role in the evolution of eukaryotes (e.g., in humans).

False

TRUE or FAlSE How is horizontal gene transfer different from vertical gene transfer? In horizontal gene transfer, genetic material is passed down from one generation to another within a species.

False

Which term describes a mutation where a chromosome breaks, and its genetic material is reinserted in a different orientation?

Inversion

If a population is in Hardy-Weinberg equilibrium, which of the following is true about this population?

None of these answers are true -Dominant allele frequency (p) is always equal to the recessive allele frequency (q) -Dominant allele frequency (p) is always larger to the recessive allele frequency (q) -Allelic frequencies are equal to the genotypic frequencies

Suppose the given data was collected on five populations of cattle. Which of the populations are in Hardy-Weinberg equilibrium? Breed DD Dd dd Shorthorn 0.36 0.48 0.16 Braunvien 0.09 0.42 0.49 Texas Longhorn 0.16 0.53 0.31 Murray Grey 0.45 0.25 0.30 Mongolian 0.20 0.58 0.22

Shorthorn Braunvien

"Antigenic shift" refers to what?

The tendency for viral genomes to evolve through the reassortment of RNA molecules of different strains

The leu marker is co-transduced with an azi 50% of the time; the leu marker is co-transduced with thr 2% of the time. What is the order of the genes?

There is not enough information to answer this question

What is a similarity between eubacteria (also known as "bacteria") and eukaryotes?

They both employ processes to ensure that only one copy of a replicated chromosome is passes on to a daughter cell

What is true about bacterial plasmids?

They can confer a selective advantage to the bacteria in which they occur

What is true about retroviruses?

They use reverse transcriptase to copy viral RNA into viral DNA

What is the point of Davis' experiment that involved separating two mutant auxotrophic strains of bacteria with a filter?

To determine whether conjugation requires cell-to-cell contact

Why did Wollman and Jacobs use a kitchen blender when looking at gene transmission from a donor Hfr strain to a recipient F- strain?

To interrupt mating at a specific time point, so that "time" could be used as a measure of distance between genes

What process of genetic transfer in bacteria involves the uptake of "free" strands of extracellular DNA?

Transformation

Which term describes the rearranging of genetic material between nonhomologous chromosomes without a net loss or gain of genetic material?

Translocation

TRUE OR FALSE. Frameshift mutations can alter all amino acids encoded by the nucleotides beyond the point of mutation, resulting in a greatly altered protein.

True

TRUE OR FALSE. Frameshift mutations can introduce premature stop codons that terminate protein synthesis.

True

What is true about a genetic cross involving two phenotypically different phages that are both single mutants?

Two recombinant classes of phage progeny will be produced

Which term refers to the transfer of genetic information from one generation to another within a species?

Vertical gene transfer

In what scenario would recombination of phages occur?

When phages of different genotypes infect a host cell

For a mammal, aneuploidy (loss of what type of individual chromosome) of what type of chromosome would lead to the least detrimental effects?

X Chromosome

Why are these effects less noticeable for multisomies and monosomies of the X chromosome in humans?

X inactivation only allows one X chromosome to be expressed in any given cell

You grow a phage strain on a lawn of "only" B strain bacteria and find that all produced plaques are large and clear (without a cloudy background). What can you conclude?

You do not have enough information to make any of these conclusions

Select the definition of polyploidy.

a chromosomal complement with at least three complete sets of homologous chromosomes

Indicate the type of mutation that gave rise to sickle cell anemia.

a transversion that leads to a missense mutation

What is the allele frequency of RR in this population? Calculate to at least two decimal places.

allele frequency of RR: 0.78

Select the definition of aneuploidy.

the addition or loss of less than a full set of chromosomes or chromosome pairs

A diploid organism has 2n=24 chromosomes. How many chromosomes will be found in a trisomic member of this species?

A chromosome has the following segments, where * represents the centromere: AB*CDEFG. How would you describe a chromosomal mutation that created this chromosome: ABC*DEFG?

Inversion

The given DNA non‑template sequence (coding sequence) is transcribed from 5' to 3'. Use the sequence to determine the type of mutation and the type of base substitutions that apply to each scenario. Place only one statement for each scenario. 5' A T G A C C G A A C G C T T G 3'

-A thymine substituted for nucleotide 6 silent and transition -A cytosine substituted for nucleotide 9 missense and transversion -An adenine substituted for nucleotide 14 nonsense and transversion

Which of the following are ways that an autotriploid (3n) may arise? Select two that apply. (Note: no unbalanced gametes are produced unless indicated.)

-From a cross between a diploid (2n) that undergo nondisjunction in meiosis and a diploid (2n) of the same species From a cross between an autotetraploid (4n) and a diploid (2n) of the same species

Both genes and environmental factors contribute to cancer. The table shows that prostate cancer is 30 times more common among Caucasians from Utah as among Chinese from Shanghai. Briefly outline how to determine if these differences in the incidence of prostate cancer are due to differences in the genetic makeup of the two populations or to differences in their environments.

-If the differences are due to the environment only, then people who migrated from Utah or Shanghai would have rates of cancer determined by their location and not by their place of origin. - If the differences are due to genetic makeup only, then people who migrated from Utah or Shanghai to elsewhere would have a similar cancer rate as people who stayed in Utah or Shanghai.

Natural selection usually eliminates the deleterious genetic mutations which cause diseases from a population. If so, how is it possible for some lethal genetic diseases to be so common in some human populations? Select all that apply.

-Mutated allele could be dominant, so individuals with just one parent with the disease have a 50-50 chance of developing the disease.• -Mutated allele causes exclusively late onset of the disease and does not affect people until after they've reproduced. -Mutation from the non-mutated allele to the mutated-allele occur more often than the reverse

A population consists of 300 individuals where 58 of them are homozygous for the red color allele (A) and 120 of them are homozygous for the blue color allele (a). What is the frequency of individuals with an AA genotype in the population?

0.19

A population consists of 300 individuals where 58 of them are homozygous for the red color allele (A) and 120 of them are homozygous for the blue color allele (a). What are the frequencies of the A and a alleles respectively?

0.395 and 0.605

0.4

0.41

The crop plants wheat and rye can be crossed to produce infertile triticale plants. Whereas the first generation hybrid is typically infertile, it is possible to generate fertile second generation hybrids. Arrange the steps used to induce allopolyploidy and fertile second generation seeds. -Mature wheat and rye plants -cross wheat and rye together - generate infertile hybrid seeds - grow first generation hybrid - treat with colchicine - doubling of chromosome ploidy fertile second generation triticale seeds

1. Mature wheat and rye plants 2. cross wheat and rye together 3. generate infertile hybrid seeds 4. grow first generation hybrid 5. treat with colchicine 6. doubling of chromosome ploidy 7. fertile second generation triticale seeds

Assume that the phenotypes of lady beetles shown in the figure are encoded by the genotypes in the table. Calculate the (𝑂-𝐸)2𝐸 value for each genotype. Match the (𝑂-𝐸)2𝐸 value for each genotype. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

1.11, 2.23, 1.11

Simulations were run on a population with an effective population (Ne) size of 1000 and 15, respectively, to simulate the change in allele frequencies over time. Ten runs were simulated across 100 generations for each population. The beginning frequencies for each allele were set at 0.50. The graphs show only the wildtype allele. Compare the graphs and determine which evolutionary force is occurring in the population of 15 Ne individuals and not in the population of 1000 Ne individuals

1000 Ne population

You have isolated two mutations that affect plaque morphology in phages (y and z). You conduct a genetic cross between the two phage strains by co-infecting bacteria with a wild-type strain and a strain that carries both the mutations y and z. Phage chromosomes enter the host and replicate. You collect some of the progeny phages and plate them onto a lawn of bacterial cells. Estimate the map distance between the y and z genes. Plaque phenotype Number y+ z+ 2980 y+ z 520 y z+ 530 y z 2970 Total 7000

You have isolated two mutations that affect plaque morphology in phages (y and z). You conduct a genetic cross between the two phage strains by co-infecting bacteria with a wild-type strain and a strain that carries both the mutations y and z. Phage chromosomes enter the host and replicate. You collect some of the progeny phages and plate them onto a lawn of bacterial cells. What is the frequency of recombination between the y and z genes? Plaque phenotype Number y+ z+ 2980 y+ z 520 y z+ 530 y z 2970 Total 7000

You have isolated two mutations that affect plaque morphology in phages (y and z). You conduct a genetic cross between the two phage strains by co-infecting bacteria with a wild-type strain and a strain that carries both the mutations y and z. Phage chromosomes enter the host and replicate. You collect some of the progeny phages and plate them onto a lawn of bacterial cells. What percentage of progeny were recombinant? Plaque phenotype Number y+ z+ 2980 y+ z 520 y z+ 530 y z 2970 Total 7000

Calculate the expected values for each genotype. If the population is in Hardy-Weinberg equilibrium, determine the expected genotype frequencies and match the expected number of individuals for each genotype, based on a population size of 11 beetles. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

2.75 5.5 2.75

You isolate two mutations in a bacteriophage. One causes bumpy plaques (b) and the other produces tiny plaques (t). Previous mapping experiments have established that the genes responsible for these mutations are 12 map units apart. You mix phages with genotypes b+ t+ and b t; you use this mixture to infect bacterial cells. After collecting and plating the progeny phages, you observe a total of 2000 plaques. What percentage (%) of the total plaques will be represented by the parental plaque types?

88% (100-12)

What will be the total number of plaques represented by the plaque type b+ t+ ?

880 (2000*.44)

Cystic Fibrosis is an autosomal recessive disease. It affects 1 of 2500 people in a population in H-W equilibrium. Estimate the frequency of homozygous unaffected people f(AA).

96%

What is most obviously an example of heteroduplex DNA?

A double stranded DNA segment that is 5' - AAGC - 3' for one strand and 3' - TCTG - 5' for the other strand

What is true about conjugation involving an Hfr cell?

A part of the episome of the donor cell is transferred into a recipient cell

Which of the following could be coded for by a tumor-suppressor gene?

A protein that helps prevent progression through the cell cycle

What happens during conjugation involving an F+ cell?

A sex pilus allows for a physical union between the F+ cell and a recipient cell

You mix 4 different Hfr strains (all with genotype a+ b+ c+ d+ e+ ) with an F- strain that has the genotype: a b c d e. You interrupt conjugation at regular intervals and determine the appearance of chromosomal genes from each Hfr strain in recipient cells. You obtain the following order of gene transfer for the four Hfr strains examined (where the letter "O" stands for the origin): Hfr1 O <-- b+ a+ c+ d+ e+ Hfr2 O <-- d+ e+ b+ a+ c+ Hfr3 O <-- b+ e+ d+ c+ a+ Hfr4 O <-- e+ d+ c+ a+ b+ What is the order of genes on the bacterial chromosome, starting with gene a?

Acdeb

Which of the features are essential to map the bacterial chromosome in a single interrupted mating experiment?

All of the features are essential when attempting to map the bacterial chromosome in a single interrupted mating experiment.

In what circumstance could you observe prototrophic recombinants in an experiment that used a filter to separate two auxotrophic bacterial strains?

All of these answer choices are possible-In the presence of a phage vector-In the presence of recombination-In the presence of transduction

Species I (AABBCC, 2n=6) and Species II (GGHHII, 2n=6) both produce haploid gametes. A hybrid is created by fusing the haploid gametes from species I and species II. Which statement about this hybrid is true?

All of these answer choices are true. -The hybrid has the same number of chromosomes as both original diploid species, so is technically considered to be diploid. -The chromosomes of the hybrid will not properly pair during meiosis, resulting in sterility -The chromosomes found in this hybrid are not homologous, thus this hybrid is functionally haploid

What is true about the type of conjugation that is called sexduction?

All of these answers are true-It involves a mating between an F'("F prime") and an F- cell-It produces donor cells that are partially diploid-It provides the possibility for recombination between genes on the bacterial chromosome and those on the F' ("F prime") factor

What is true with respect to bacteria and viruses?

All of these answers are true. -Information on bacterial and viral genetics can provide insight into genetic principles that are applicable to humans-Bacteria and viruses can be harnessed for human use, e.g. to produce economically important substances-Bacteria and viruses play important roles in the world's ecosystem, e.g. marine bacteria produce 50% of the world's oxygen

An F- cell contains mutant versions of the genes: x, y, and z. A Hfr cell contains the wildtype versions, x+, y+, and z+. What could result following conjugation?

An F- cell that has the genotype x, y, z+

Which organism is polyploid?

Between the genes b and e

This second generation also reproduces to produce a third generation. All of the rules that applied to the parent population also apply to the second generation. Which is true about the third generation of this population?

Both genotypic and allele frequencies will remain the same as they were in the parent population.

Phages can be used to locate the relative position of bacterial genes on the bacterial chromosome. To this end, you use phages to conduct a three-factor transduction cross for the chromosomal genes a, b, and c in bacteria. You use a+ b+ c+ as donor bacterial cells and a b c as recipient bacterial cells. You select for the marker a+ in recipient bacterial cells and determine the number of times that phages transferred the other (unselected) markers from donor cells together with a+. You obtain the following information: Which gene is closest to gene marker a? Unselected markers Number b c+ 24 b+ c+ 8 b+ c 1

Cancer cells divide uncontrollably, evading the signals that regulate the cell cycle. Classify the characteristics as those of cancer cells or normal cells.

Cancer cells -have abnormal number of chromosomes -enter new tissues and grow there -do not stop dividing when crowded Normal cells -differentiate into specialized cells -self‑destruct if nucleus is abnormal -adhere to neighboring cells within a tissue

An Hfr bacterial strain with a genotype of amps, gal+, leu+, cys+, thr+ was used in an interrupted mating experiment with an F- bacterial strain with genotype ampr, gal-, leu-, cys-, thr-. At regular intervals, the mating was interrupted and bacteria were selected with ampicillin and tested for the transfer of Hfr alleles into the F- bacteria. The time required to transfer the donor genes is shown in the table. Which gene is closest to the leading side of the F factor origin of transfer?

Cys Gene transferred Time cys 3 min thr 6 min gal 10 min leu 12 min

A group of scientists were studying a particular gene locus (D) of mice. They collected 200 animals and determined their locus-specific genotypes. The data collected is shown in the table. Calculate genotypic frequencies for the population. Genotype #of individuals Genotypic Frequency DD 10 Dd 42 dd 148 Allele Allelic Frequency D d Calculate genotypic frequencies for the population.

D: 0.155 d: 0.845 Equation p=f(D) = 2n subscript (DD)+ n subscript (Dd) / divided by 2N p= f(d) = 2n subscript (dd) + n subscript (Dd) /2N n(DD) = number of DD individuals n (Dd) =number of Dd individuals n(dd)=number of dd individuals N=total number of individuals

DD: 0.05 Dd: 0.21 dd: 0.74 (genotypic frequency = # of individuals/total # individuals in population)

During meiosis, errors can occur during chromosome replication. Which term describes the addition of genetic material to a chromosome through extra replication of a chromosomal section?

Duplication

Which of the statements describes what happens during mismatch repair of DNA?

Enzymes identify the recently copied DNA strand, snip out a portion of the DNA strand that contains the mismatched nucleotides, and resynthesize the segment correctly.

Huntington's disease. Huntington's disease is a fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain. In general, Huntington's disease is rare among humans. However, a high frequency of Huntington's disease has been recorded in Lake Maracaibo (Western Venezuela) since the 1970s.The high incidence of this disease in Lake Maracaibo compared to other regions could be best explained by:

Founder Effect

What is true about the CRISPR-Cas system in bacteria?

Fragments of phage DNA are incorporated as spacers into sequences on the bacterial chromosome called CRISPR's

Frank has Klinefelter syndrome (47, XXY). His mother has normal skin, but his father has anhidrotic ectodermal dysplasia, an X linked condition where the skin does not contain sweat glands. Frank has patches of normal skin and patches of skin without sweat glands. Complete the sentences. Some answers may be used more than once or not at all.

Frank received the mutant chromosome from his FATHER . Nondisjunction occurred in his FATHER during the 1st meiotic division.

Hemoglobin is a complex protein that contains four polypeptide chains. The normal hemoglobin found in adults, called adult hemoglobin, consists of two alpha and two beta polypeptide chains, which are encoded by different loci. Sickle cell hemoglobin, which causes sickle cell anemia, arises from a single mutation in the beta chain of adult hemoglobin. Adult hemoglobin and sickle cell hemoglobin differ in a single amino acid. The sixth amino acid from one end in adult hemoglobin is glutamic acid, whereas sickle cell hemoglobin has valine at this position. After consulting a codon table, indicate the mutant codons that could give rise to sickle cell anemia.

GUG GUA

An Hfr bacterial strain contains the genes a+, b+, c+, d+, f+, and strS in an unknown order. An F− bacterial strain contains the genes a, b, c, d, f, and strR also in an unknown order. The Hfr bacterial strain is mated with the F− strain. The mating is interrupted at different time points, and samples are plated onto selective media to assay for gene function. The frequencies of each recombinant are shown. Determine the linear order of the genes of the Hfr chromosome using strR as a reference point.

Gene 1 b+ Gene 2 f+ Gene 3 a+ Gene 4 c+ Gene 5 d+

Chromosome duplications and deletions frequently result in abnormal phenotypes or inviable gametes. Which factor is a major contributor to this phenomenon?

Gene dosage is modified

Which of the following change is a transition base substitution?

Guanine replaced by adenine

Cancers may be either inherited or they may be induced by environmental factors such as carcinogens and radiation. Select the statement that explains how diverse factors such as hereditary events and environmental agents can both cause cancer.

Hereditary and environmental factors involve mutations that affect the cell cycle.

You mix 4 different Hfr strains (all with genotype a+ b+ c+ d+ e+ ) with an F- strain that has the genotype: a b c d e. You interrupt conjugation at regular intervals and determine the appearance of chromosomal genes from each Hfr strain in recipient cells. You obtain the following order of gene transfer for the four Hfr strains examined (where the letter "O" stands for the origin): Hfr1 O <-- b+ a+ c+ d+ e+ Hfr2 O <-- d+ e+ b+ a+ c+ Hfr3 O <-- b+ e+ d+ c+ a+ Hfr4 O <-- e+ d+ c+ a+ b+ The polarity of the F factor in Hfr strain 4 is the same as the polarity of the F factor in which other strain?

Hfr3

A phage infects a bacterium. What scenario could lead to transduction in this bacterium?

If a fragment of bacterial DNA was erroneously packaged into the head of the phage

If you extract DNA from a bacterium, break up the DNA into fragments, and use the fragments to transform recipient bacteria. What must be true?

If the p and q genes are transmitted to the recipient bacteria together, then these genes must be closely linked

Where can DNA be found in bacteria?

In plasmids

What is true regarding specialized transduction?

In specialized transduction, only certain sections of the bacterial chromosome can be transduced

What is true about the life cycle of phages?

In the lysogenic cycle, a phage chromosome incorporates itself into the genome of a bacterium

What is true about the lytic cycle of phages?

In the lytic cycle, bacterial ribosomes are inducted to produce phage proteins

Two brothers have X linked red-green colorblind vision, and their parents have normal color vision. The first brother's karyotype is 47,XXY (Klinefelter syndrome), and the second brother's karyotype is 46,XY. In which parent and in what cell division phase did the first brother's chromosomal nondisjunction occur? Assume no recombination.

In the mother in meiosis II

Which can be accomplished by an interrupted mating experiment between Hfr and F- bacteria?

Interrupted mating experiments can determine gene order on the Hfr bacterial chromosome.

Using a chi square critical values table, determine the best interpretation for the chi square value of 4.45 for this data set. A 𝑝 value of 0.05 is considered statistically significant. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

It is unlikely that the lady beetles are in Hardy-Weinberg equilibrium.

What is true regarding horizontal gene transfer?

It might affect predictions regarding the phylogeny of species, especially when these are based on the absence/presence of genes

What is true about the transfer of bacterial genes through transduction?

It requires the participation of phage vectors

Why is recombination into the bacterial chromosome necessary?

Linear DNA is unstable in bacterial cells and unless the lac+ gene is recombined into the bacterial chromosome, it will be destroyed.

Classify whether each of the characteristics belong to the lytic cycle, lysogenic cycle, or both.

Lytic the bacterial cell wall is broken open the host DNA is degraded Lysogenic the phage genome is incorporated into the bacterial chromosome the phage genome replicates with the host DNA Both the phage genome enters the host cell

The image portrays a representation of a human karyotype. What type of genetic disorder is shown in this karyotype?

MONOSOMY

What is true about use of Hfr strains in the generation of genetic linkage maps in bacteria?

Making such maps requires a large, random population of bacteria represented by many Hfr strains

Mature wheat and rye plants

Aneuploidy is an umbrella term referring to multiple kinds of conditions in which an individual has an abnormal number of chromosomes for their species. Some of the patients on the abnormal tab of the karyotype virtual interactive suffer from different types of aneuploidy. Use the interactive to determine from which form of aneuploidy patient 367 suffers.

Monosomy

How does cancer differ from most other genetic disorders?

Most genetic disorders are inherited through germ cells from parents. Most cancers are, to some extent, the result of mutations in somatic cells that occur during an organism's lifetime.

Which term describes the process of sister chromatids not separating at the centromere during cell division?

Nondisjunction

What is true about the modified F factor that is called F'(leu)?

The modified F factor contains the leu gene region from the bacterial chromosome

On what type of medium will a mutant auxotrophic strain that is unable to synthesize the essential nutrient leucine be able to grow?

One minimal medium that lacks methionine and biotin

A mating between two mutant auxotrophic strains results in recombinant cells that are prototrophic. What's most likely?

One of the original auxotrophic strains was an F-strain

The color distribution for a specific population of snakes is 170 red, 50 orange, and 30 yellow. The allele for the color red is represented by RR, whereas the allele for the color yellow is represented by RY. Both alleles demonstrate incomplete dominance. What are the genotype frequencies in the population? Calculate to at least two decimal places.

RRRR : 0.68 RRRY : 0.20 RYRY : 0.12

Following transfer of DNA from Hfr donor cell to an F- recipient cell, what might happen?

Recombination might replace a gene in the F- cell's chromosome with a gene from the Hfr cell's chromosome

In humans, red blood cells have a number of proteins embedded in the cell membrane. One type of protein, the Rh factor, is controlled by a single gene and is either present or missing from the red blood cells. If present, the individual has the Rh+ phenotype. If missing, the individual has the Rh− phenotype. Rh+ is the dominant to Rh−. Suppose that, in the Yoruban population, the frequency of the Rh− phenotype is 0.01.0.01. Using the Hardy-Weinberg equations, calculate the frequency of the Rh+ allele to at least two decimal places.

Rh+ allele frequency: 0.9

Classify each definition or example as a somatic mutation, gametic (germ line) mutation, or both. The mutation occurs in any cell except a germ cell, and thus the mutation does not affect the progeny of the individual. A particular tobacco leaf becomes discolored due to a mutation halfway through the life of the plant. The mutation originates in the reproductive cells of an individual and affects their offspring. A man receives a pelvic X‑ray. Nine months later, his child is born with a chromosomal abnormality. Mutations can be caused by an alteration in the DNA sequence.

Somatic mutation -The mutation occurs in any cell except a germ cell, and thus the mutation does not affect the progeny of the individual. -A particular tobacco leaf becomes discolored due to a mutation halfway through the life of the plant. Gametic mutation -The mutation originates in the reproductive cells of an individual and affects their offspring. -A man receives a pelvic X‑ray. Nine months later, his child is born with a chromosomal abnormality. Both -Mutations can be caused by an alteration in the DNA sequence.

In this type of transduction, a piece of bacterial chromosome is acquired by the phage chromosome; that is, phages carry viral DNA covalently linked to bacterial DNA.

Specialized transduction

What are the three stages by which CRISPR Cas immunity occurs, and what takes place during each stage?

Stage 1: Adaption - Foreign DNA is cleaved and incorporated into the CRISPR-Cas array as spacers Stage 2: Expression - The CRISPR array is transcribed and processed to produce CRISPR RNA that combines with a Cas protein to form an effector complex Stage 3: Interference - The effector complex binds to foreign DNA and the Cas protein cleaves the foreign DNA, which is then degraded

In the lower half of the interactive, change the template DNA strand such that the sequence ...ACAAAC...is changed to ...ACATAC... Which of the terms correctly describes this type of mutation?

Substitution

In the lower half of the interactive, change the template DNA strand such that the sequence...AACCTG......AACCTG...is changed to...AACTTG......AACTTG...Which of the terms correctly describes this type of mutation?

Substitution

The table contains the DNA sequence for a segment of the human insulin gene and the same DNA sequence with a mutation. Which type of mutation occurred in the original sequence to generate the mutated sequence? Original sequence ATG CGC CTC CTG CCC CTG CTG GCG Mutated sequence ATG CGC CTC CTT CCC CTG CTG GCG

Substitution

An alteration in the nucleotide sequence of a gene can alter the gene product. Each sentence is made up of three‑letter words, representing mRNA codons. THE FAT CAT SAT THE CAR WAS RED SHE HAS THE DOG The same sentences are written with a substitution, deletion, or insertion, much as a gene may have a substitution, deletion, or insertion mutation. Identify which sentence represents a substitution, which represents a deletion, and which represents an insertion.

Substitution THE CAT WAS RED Deletion SHE HAS THE DG Insertion THE FAT ACA TSA T

Match the definitions to the appropriate terms that describe the number of chromosomes. Tetraploid Tetrasomic 𝑛=4 four homologues of each chromosome two extra copies of a specific chromosome a genome composed of four unique chromosomes

Tetraploid four homologues of each chromosome Tetrasomic two extra copies of a specific chromosome 𝑛=4 a genome composed of four unique chromosomes

What was Hayes' main conclusion about conjugation following his experiments in 1953?

That only one of the bacterial strains serves as the recipient of genetic material

A phage can acquire bacterial genes through imprecise excision. An F factor that acquires chromosomal genes through a similar mechanism will produce what?

The F' cell

What best describes the most common fate of an F- bacterium after conjugation with an Hfr bacterium?

The F- bacterium remains F- but might also undergo a phenotypic change resulting from recombination.

The individuals of this population mate randomly and never move (i.e., there is no migration into or out of the population), and mutation also does not occur. Each couple has two children and the parents die after having their second child, so the population size does not change. Answer the questions about this population after the parents have had both children and are dead. Which is true about the next generation of this population?

The allele frequencies will remain the same as they were in the parent population.

What must be true for an F- cell to be converted to an Hfr cell?

The entire integrated F factor of the Hfr cell must be transferred

Transformation can be used to map bacterial genes. You obtain a donor bacterium with the wildtype genes r+, s+, and t+. You extract DNA from this population of donor bacteria and break this DNA up into fragments. You use these fragments to transform recipient bacteria that have mutant genes at all three loci. Here is the data that shows the transformed cell genotypes for recipient bacteria. Based on the data above, determine which two genes are located farthest apart from each other. Transformed cell genotypes r s t+ r s+ t r s+ t+ r+ s t+ r+ s t

The genes r and s

The leu marker is co-transduced with an azi 50% of the time; the leu marker is co-transduced with thr 2% of the time. What must be true?

The leu and azi markers must be located closer together on the bacterial chromosome than the leu and thr markers

Red green color blindness is a human X linked recessive disorder. The normal allele, XB, is dominant to the mutant allele, Xb. Jill has normal color vision, but her father is color blind. Jill marries Tom, who also has normal color vision. Jill and Tom have a daughter who has Turner syndrome and is color blind. How and from whom did the daughter inherit color blindness?

an ovum carrying Xb followed by fertilization by sperm from a paternal nondisjunction event

This tutorial will take you step by step through the question. Assume that the phenotypes of lady beetles shown in the figure are encoded by the genotypes in the table. How many black lady beetles are in the figure? Phenotype Genotype all black BB some black spots Bb no black spots bb

black beetles: 1

An Hfr bacterial strain with a genotype of amps, gal+, leu+, cys+, thr+ was used in an interrupted mating experiment with an F- bacterial strain with genotype ampr, gal-, leu-, cys-, thr-. At regular intervals, the mating was interrupted and bacteria were selected with ampicillin and tested for the transfer of Hfr alleles into the F- bacteria. The time required to transfer the donor genes is shown in the table. What is the order of genes on the Hfr donor chromosome?

both leu gal thr cys and cys thr gal leu are correct Gene transferred Time cys 3 min thr 6 min gal 10 min leu 12 min

Tay-Sachs disease is an autosomal recessive disorder. Homozygous recessive individuals lack a key enzyme called hexosaminidase A, which presents as progressive mental and motor deterioration until death occurs around age 5. Heterozygous individuals, called Tay-Sachs carriers, develop no symptoms of the disease. Tay-Sachs disease was historically more prevalent within populations of Ashkenazi Jews, Pennsylvania Dutch, southern Louisiana Cajuns, and eastern Quebec French Canadians. Today, individuals descended from these populations are more likely to be Tay-Sachs carriers, but genetic testing within these populations has largely eliminated the occurrence of Tay-Sachs disease. For a randomly mating population, calculate the Tay-Sachs carrier frequency to three decimal points if 1 in 3600 individuals develops Tay-Sachs disease.

carrier frequency: 0.033

Determine the degrees of freedom and interpret the chi square value. Determine the degrees of freedom (𝑑𝑓) needed to conduct a chi square test for the data. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

degrees of freedom: 1

Which type of DNA mutation results in a change in the reading frame of an mRNA?

deletion of a single nucleotide

Now you can use the step by step method to answer these challenging questions. For the lady beetles shown in the figure, calculate the frequencies of the genotypes and frequencies of the alleles. Be sure to round your answers to two decimal places. . 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

frequency of BB genotype: 0.09 frequency of Bb genotype: 0.81 frequency of bb genotype: 0.09 frequency of B allele: 0.5 frequency of b allele: 0.5

Suppose the human trait for dimples is controlled by a simple dominant and recessive relationship at one locus. Dimples, D, is the dominant allele, and a lack of dimples, d, is the recessive allele. In a college genetics class, the professor takes a tally of students who have dimples and of students with a lack of dimples. In this class of 117117 students, 3737 have dimples. Calculate the frequency of the dominant allele, D, and the heterozygous genotype, Dd. Express the frequencies in decimal form rounded to the nearest thousandth. Assume the class is in Hardy-Weinberg equilibrium for this trait.

frequency of D: 0.173 frequency of Dd: 0.286

Simulations were run on a population with an effective population (Ne) size of 1000 and15, respectively, to simulate the change in allele frequencies over time. Ten runs were simulated across 100 generations for each population. The beginning frequencies for each allele were set at 0.50. The graphs show only the wildtype allele.Compare the graphs and determine which evolutionary force is occurring in the population of 15 Ne individuals and not in the population of 1000 Ne indviduals.

genetic drift

genotype frequency of BB: 0.09

genotype frequency of Bb: 0.82

genotype frequency of bb: 0.09

Jean Manning, Charles Kerfoot, and Edward Berger studied the genetic frequencies at the phosphoglucose isomerase (GPI) locus in the cladoceran Bosmina longirostris. From one location at Union Bay in Seattle, Washington, they collected 176 animals and determined their GPI genotypes by using electrophoresis. The data they collected is shown in the table. Calculate the genotypic and allelic frequencies for the population using three decimal places. Genotype Number 𝑆1𝑆1 4 𝑆1𝑆2 38 𝑆2𝑆2 134

genotypic frequency for 𝑆1𝑆1: 0.023 genotypic frequency for 𝑆2𝑆2: 0.762 genotypic frequency for 𝑆1𝑆2: 0.216 allelic frequency for 𝑆1: 0.131 allelic frequency for 𝑆2: 0.869

In general, what causes normal cells to become cancer cells?

loss of cell cycle control

A generalized transduction experiment is set up so that a phage is carrying a donor strain with the genotype met+ bio+ thr+. This donor strain is used to transduce a recipient E. coli strain with the genotype met− bio− thr−. After transduction, the recipient population is plated on a minimal medium containing only organic salts and a simple carbon source supplemented with methionine and biotin. A large number of colonies are obtained. The wild type genes indicate the bacteria do not need a supplemented minimal medium in order to grow. Any bacteria with mutant genes will require a supplement of methionine, biotin, or threonine to grow. The use of minimal medium without all the required nutrients is a type of marker selection. Marker selection utilizes the inability of some bacteria with mutant genotypes to grow on minimal medium by creating a medium that only select bacteria can grow on. Select the possible genotypes of the colonies that grew on this medium.

met+ bio+ thr+ and- met− bio− thr+

If this mutation occurred in a protein coding gene, how would it be classified?

missense mutation

If this mutation occurred in a protein coding gene, how would it be classified?

nonsense mutation

Full color (D) in domestic cats is dominant over dilute color (d). Out of 325 cats observed, 194 have full color and 131 have dilute color. If these cats are in Hardy-Weinberg equilibrium for the dilution locus. Calculate the expected number of heterozygous cats out of the 194 cats with a full color coat phenotype.

number of heterozygotes: 151

p=f (D) = 0.155 q=f (d) = 0.845 Equation p= f(D) = f(DD) + 1/2 f(Dd) q= f(d) = F(dd) + 1/2 f(Dd) f(DD)=frequency of genotype DD f(Dd) = frequency of genotype Dd f(dd) = frequency of genotype dd

In this mouse population, there are 100 individuals; 5 of them possess D1D1 genotype. Calculate the D1 allele frequencies using the information below. D1D2 = 10 individuals D1D3 = 22 individuals D2D3 = 48 individuals

p=f (D1) = 0.21

population: 11

You have isolated two mutations that affect plaque morphology in phages (y and z). You conduct a genetic cross between the two phage strains by co-infecting bacteria with a wild-type strain and a strain that carries both the mutations y and z. Phage chromosomes enter the host and replicate. You collect some of the progeny phages and plate them onto a lawn of bacterial cells. You observe the following number of plaques: Which are examples of recombinant progeny? Select all that apply. Plaque phenotype Number y+ z+ 2980 y+ z 520 y z+ 530 y z 2970 Total 7000

y+ z y z+

In a transformation experiment, the genes x and y are transmitted together as well as the genes x and z, but not the genes z and y. What is the gene order?

z-x-y

Full color (D) in domestic cats is dominant over dilute color (d). Out of 325 cats observed, 194 have full color and 131 have dilute color. If these cats are in Hardy-Weinberg equilibrium for the dilution locus, calculate the frequency of the d allele. Use three decimal places for the answer.

𝑓(𝑑)= 0.635

This tutorial will take you step by step through the question. Assume that the phenotypes of lady beetles shown in the figure are encoded by the genotypes in the table. Phenotype Genotype all black BB some black spots Bb no black spots bb Calculate allele frequencies. Use the equation to calculate the frequency of the B allele (𝑝), where 𝑛𝐵𝐵 and 𝑛𝐵𝑏 represent the number of beetles of each genotype and 𝑁 is the total number of beetles in the population.

𝑝=𝑓(𝐵)=(2𝑛𝐵𝐵+𝑛𝐵𝑏)2𝑁 𝑝= 0.5

𝑞= 0.5

𝑞coastal= 0.63 𝑞inland= 0.40

In a species of bird, the allele for the striped trait is recessive to the allele for the speckled trait. Suppose that a coastal bird population has a striped phenotype frequency of 0.390.39 and an inland population has a striped phenotype frequency of 0.16.0.16. The two populations are isolated and in Hardy-Weinberg equilibrium. Let 𝑞coastal represent the allele frequency of the coastal population and 𝑞inland represent the allele frequency of the inland population. After an exceptionally rainy spring, there is no longer a barrier between the populations, and some individuals migrate inland from the coast. Consequently, 10%10% of individuals in the new inland population are originally from the coastal population. Calculate the striped allele frequency for the inland population after migration, 𝑞combined. Round the answer to the nearest hundredth.

𝑞combined= 0.42

Assume that the phenotypes of lady beetles shown in the figure are encoded by the genotypes in the table.Using the table showing the observed (𝑂) and expected (𝐸) data, calculate the 𝜒2 value. Round your answer to two decimal places. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

𝜒2= 4.45

Determine if the population is in Hardy-Weinberg equilibrium by using a chi square test and referring to a chi-square critical values table. Be sure to round your answer to two decimal places. 𝑂 𝐸 (𝑂−𝐸) (𝑂−𝐸)2 (𝑂−𝐸)2𝐸 BB 1 2.75 −1.75 3.06 1.11 Bb 9 5.5 3.5 12.25 2.23 bb 1 2.75 −1.75 3.06 1.11

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