Question 1

The hypothesis that predicts no linkage between genes is known as the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 2

In ascomycete fungi, the arrangement of the spores in the ascus that directly reflects the order in which they were produced during meiosis is called an ______.

Accepted Answer

A) Unordered tetrad 
B) Unordered octad 
C) Ordered tetrad 
D) Ordered pentad 
A) Unordered tetrad 
B) Unordered octad 
C) Ordered tetrad 
D) Ordered pentad

Question 3

A crossover that would result in genetic recombination (e.g., Abc or aBC) could involve which chromatids?

Accepted Answer

A) 1 & 2 or 3 & 4 
B) 1 & 3 or 2 & 4 
C) 1 & 4 or 2 & 3 
D) 1 & 3 or 1 & 4 or 2 & 3 or 2 & 4 
E) any two of the four chromatids 
A) 1 & 2 or 3 & 4 
B) 1 & 3 or 2 & 4 
C) 1 & 4 or 2 & 3 
D) 1 & 3 or 1 & 4 or 2 & 3 or 2 & 4 
E) any two of the four chromatids

Question 4

Suppose a woman has four sons, and two are colorblind but have normal blood clotting and two have hemophilia but normal color vision.What is the probable genotype of the woman?

Accepted Answer

A) HR / hr 
B) Hr / hr 
C) hr / hR 
D) Hr / hR 
E) HR / Hr 
A) HR / hr 
B) Hr / hr 
C) hr / hR 
D) Hr / hR 
E) HR / Hr

Question 5

A female mouse from a true-breeding wild-type strain was crossed to a male mouse with apricot eyes (ap) and grey body (gy).The F1 mice were wild-type for both traits.When the F1 were interbred, the F2 were distributed as follows:   Which of the following statements is correct?

Accepted Answer

A) ap and gy are unlinked. 
B) ap and gy are linked on an autosome and 10 map units apart. 
C) ap and gy are linked on an autosome and 20 map units apart. 
D) ap and gy are X-linked and 10 map units apart. 
E) ap and gy are X-linked and 20 map units apart. 
A) ap and gy are unlinked. 
B) ap and gy are linked on an autosome and 10 map units apart. 
C) ap and gy are linked on an autosome and 20 map units apart. 
D) ap and gy are X-linked and 10 map units apart. 
E) ap and gy are X-linked and 20 map units apart.

Question 6

The measured distance between genes D and E in a two point test cross is 50 map units.What does this mean in physical terms?

Accepted Answer

A) D and E are on different pairs of chromosomes. 
B) D and E are linked and exactly 50 map units apart. 
C) D and E are linked and at least 50 map units apart. 
D) either D and E are on different pairs of chromosomes or D and E are linked and exactly 50 map units apart 
E) either D and E are on different pairs of chromosomes or D and E are linked and at least 50 map units apart 
A) D and E are on different pairs of chromosomes. 
B) D and E are linked and exactly 50 map units apart. 
C) D and E are linked and at least 50 map units apart. 
D) either D and E are on different pairs of chromosomes or D and E are linked and exactly 50 map units apart 
E) either D and E are on different pairs of chromosomes or D and E are linked and at least 50 map units apart

Question 7

If an individual is heterozygous at two loci (Ab/aB) which are on the same chromosome arm with the A locus closest the centromere under what conditions would a crossover in a somatic cell generate a twin spot?

Accepted Answer

A) The crossover would have to occur between the A locus and the centromere locus and involve two homologous (non-sister) chromatids. 
B) The crossover would have to occur between the A locus and the B locus and involve two homologous (non-sister) chromatids. 
C) The crossover would have to occur between the B locus and the end of the chromosome locus and involve two homologous (non-sister) chromatids. 
D) A double crossover would have to occur, with one crossover between the A locus and the centromere and a second crossover between the A and B loci locus and both crossovers would have to involve two homologous (non-sister) chromatids. 
E) No crossover in a somatic cell could generate a twin spot. 
A) The crossover would have to occur between the A locus and the centromere locus and involve two homologous (non-sister) chromatids. 
B) The crossover would have to occur between the A locus and the B locus and involve two homologous (non-sister) chromatids. 
C) The crossover would have to occur between the B locus and the end of the chromosome locus and involve two homologous (non-sister) chromatids. 
D) A double crossover would have to occur, with one crossover between the A locus and the centromere and a second crossover between the A and B loci locus and both crossovers would have to involve two homologous (non-sister) chromatids. 
E) No crossover in a somatic cell could generate a twin spot.

Question 8

What is the genotype of the tall, red, wide-leaved parent?

Accepted Answer

A) Tt Rr Ww 
B) Tt Rr WW 
C) TT RR WW 
D) TT Rr Ww 
E) TT RR Ww 
A) Tt Rr Ww 
B) Tt Rr WW 
C) TT RR WW 
D) TT Rr Ww 
E) TT RR Ww

Question 9

Which classes are the parental types?

Accepted Answer

A) wild-type and orange 
B) brown and bright-red 
C) wild-type and brown 
D) bright-red and orange 
E) There is no way to determine this. 
A) wild-type and orange 
B) brown and bright-red 
C) wild-type and brown 
D) bright-red and orange 
E) There is no way to determine this.

Question 10

In tetrad analysis, second-division segregations result from

Accepted Answer

A) single crossovers between linked genes. 
B) double crossovers between linked genes. 
C) single crossovers between a gene and a centromere. 
D) independent assortment of unlinked genes. 
E) nondisjunction of homologs. 
A) single crossovers between linked genes. 
B) double crossovers between linked genes. 
C) single crossovers between a gene and a centromere. 
D) independent assortment of unlinked genes. 
E) nondisjunction of homologs.

Question 11

The R/r and S/s genes are linked and 10 map units apart.In the cross Rs/rS * rs/rs what fraction of the progeny will be RS/rs?

Accepted Answer

A) 5% 
B) 10% 
C) 25% 
D) 40% 
E) 45% 
A) 5% 
B) 10% 
C) 25% 
D) 40% 
E) 45%

Question 12

Calculate the coefficient of coincidence in this region.

Accepted Answer

A) 0 
B) 0.16 
C) 0.33 
D) 0.5 
E) 0.66 
A) 0 
B) 0.16 
C) 0.33 
D) 0.5 
E) 0.66

Question 13

Sturtevant's detailed mapping studies of the X chromosome of Drosophila established what genetic principle?

Accepted Answer

A) That genes are arranged in a linear order on the chromosomes. 
B) That genes are carried on chromosomes. 
C) That sex determination is controlled by the X and Y chromosomes. 
D) That segregation of an allelic gene pair is accompanied by disjunction of homologous chromosomes. 
E) That different pairs of chromosomes assort independently. 
A) That genes are arranged in a linear order on the chromosomes. 
B) That genes are carried on chromosomes. 
C) That sex determination is controlled by the X and Y chromosomes. 
D) That segregation of an allelic gene pair is accompanied by disjunction of homologous chromosomes. 
E) That different pairs of chromosomes assort independently.

Question 14

If two or more of the genes are linked, what map distance separates them?

Accepted Answer

A) 4 mu 
B) 12 mu 
C) 24 mu 
D) 50 mu 
E) None of the genes are linked to each other. 
A) 4 mu 
B) 12 mu 
C) 24 mu 
D) 50 mu 
E) None of the genes are linked to each other.

Question 15

Chiasmata are structures of cross over between sister chromatids of homologous chromosomes.

Accepted Answer

A) True 
 B)False

Question 16

ws; ws; ws+; ws+; ws; ws; ws+; ws+

Accepted Answer

A) First-division segregation pattern 
B) Second-division segregation pattern 
A) First-division segregation pattern 
B) Second-division segregation pattern

Question 17

A coefficient of coincidence of 0.5 in a region of three genes means that half as many double crossovers were observed as would have been expected if crossovers in the two intervals were independent.

Accepted Answer

A) True 
 B)False

Question 18

How many degrees of freedom are there?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
A) 1 
B) 2 
C) 3 
D) 4

Question 19

The zipper-like connection between paired homologs in early prophase is known as a

Accepted Answer

A) spindle fiber. 
B) synaptic junction. 
C) synaptonemal complex. 
D) chiasma. 
E) none of the choices are correct. 
A) spindle fiber. 
B) synaptic junction. 
C) synaptonemal complex. 
D) chiasma. 
E) none of the choices are correct.

Question 20

Genes Q and R are 20 map units apart.If a plant of genotype QR / qr is selfed, what percentage of the progeny will be qr in phenotype?

Accepted Answer

A) 4% 
B) 10% 
C) 16% 
D) 20% 
E) 40% 
A) 4% 
B) 10% 
C) 16% 
D) 20% 
E) 40%

Exam 5: Linkage, Recombination, and the Mapping of Genes on Chromosomes

The hypothesis that predicts no linkage between genes is known as the null hypothesis.

In ascomycete fungi, the arrangement of the spores in the ascus that directly reflects the order in which they were produced during meiosis is called an ______.

A crossover that would result in genetic recombination (e.g., Abc or aBC) could involve which chromatids?

Suppose a woman has four sons, and two are colorblind but have normal blood clotting and two have hemophilia but normal color vision.What is the probable genotype of the woman?

A female mouse from a true-breeding wild-type strain was crossed to a male mouse with apricot eyes (ap) and grey body (gy).The F1 mice were wild-type for both traits.When the F1 were interbred, the F2 were distributed as follows: Which of the following statements is correct?

The measured distance between genes D and E in a two point test cross is 50 map units.What does this mean in physical terms?

If an individual is heterozygous at two loci (Ab/aB) which are on the same chromosome arm with the A locus closest the centromere under what conditions would a crossover in a somatic cell generate a twin spot?

What is the genotype of the tall, red, wide-leaved parent?

Which classes are the parental types?

In tetrad analysis, second-division segregations result from

The R/r and S/s genes are linked and 10 map units apart.In the cross Rs/rS * rs/rs what fraction of the progeny will be RS/rs?

Calculate the coefficient of coincidence in this region.

Sturtevant's detailed mapping studies of the X chromosome of Drosophila established what genetic principle?

If two or more of the genes are linked, what map distance separates them?

Chiasmata are structures of cross over between sister chromatids of homologous chromosomes.

ws; ws; ws+; ws+; ws; ws; ws+; ws+

A coefficient of coincidence of 0.5 in a region of three genes means that half as many double crossovers were observed as would have been expected if crossovers in the two intervals were independent.

How many degrees of freedom are there?

The zipper-like connection between paired homologs in early prophase is known as a

Genes Q and R are 20 map units apart.If a plant of genotype QR / qr is selfed, what percentage of the progeny will be qr in phenotype?

Genetics: The Study of Biological Information

Mendels Principles of Heredity

Extensions to Mendels Laws

The Chromosome Theory of Inheritance

DNA Structure, Replication, and Recombination

Anatomy and Function of a Gene: Dissection Through Mutation

Gene Expression: The Flow of Information From DNA to RNA to Protein

Digital Analysis of Genomes

Analyzing Genomic Information

The Eukaryotic Chromosome

Chromosomal Rearrangements and Changes in Chromosome Number

Bacterial Genetics

Organellar Inheritance

Gene Regulation in Prokaryotes

Gene Regulation in Eukaryotes

Manipulating the Genomes of Eukaryotes

The Genetic Analysis of Development

The Genetics of Cancer

Variation and Selection in Populations

Genetics of Complex Traits

Filters

A female mouse from a true-breeding wild-type strain was crossed to a male mouse with apricot eyes (ap) and grey body (gy).The F₁ mice were wild-type for both traits.When the F₁ were interbred, the F₂ were distributed as follows: Which of the following statements is correct?

ws; ws; ws⁺; ws⁺; ws; ws; ws⁺; ws⁺