Question 1

In tetrad analysis, NPD asci result from

Accepted Answer

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

Question 2

What is the map distance between the pr and cn genes?

Accepted Answer

A) 20 m.u. 
B) 2 m.u. 
C) 4 m.u. 
D) 46 m.u. 
E) 8 m.u.

Question 3

The map of a chromosome interval is: A--10 mu--B--40 mu--C
From the cross Abc / aBC * abc / abc, how many double crossovers would be expected out of 1000 progeny?

Accepted Answer

A) 5 
B) 10 
C) 20 
D) 40 
E) 80

Question 4

Crossing over takes place in paired bivalents consisting of ______ chromatids, and involves _______ of the chromatids.

Accepted Answer

A) 2, 2 
B) 2, 4 
C) 4, 2 
D) 4, 4 
E) 8, 4

Question 5

What is the $ \chi$2 value for a test of the null hypothesis?

Accepted Answer

A) 0.5 
B) 1.0 
C) 2.0 
D) 0.4 
E) 20

Question 6

Suppose a three-point testcross was conducted involving the genes X, Y, and Z.If the most abundant classes are XYz and xyZ and the rarest classes are xYZ and Xyz, which gene is in the middle?

Accepted Answer

A) X 
B) Y 
C) Z 
D) cannot be determined

Question 7

What is the coefficient of coincidence in this region?

Accepted Answer

A) 0 
B) 0.2 
C) 0.4 
D) 0.6 
E) 0.8

Question 8

Calculate the $ \chi$2 value used test the hypothesis that the C and D genes are unlinked.

Accepted Answer

A) 0 
B) 0.0576 
C) 10.8 
D) 14.4 
E) Cannot be determined

Question 9

The cross Lpq / lPQ * lpq / lpq is carried out and the L gene is found to be in the middle.What would be the genotypes of the double crossover gametes in this cross?

Accepted Answer

A) LPQ and lpq 
B) LpQ and lPq 
C) lpQ and LPq 
D) Lpq and lPQ 
E) cannot be determined

Question 10

Which statement(s) below apply to the concept of gene linkage? 
A.The different alleles of two or more genes that are on a chromosome are inherited in an manner inconsistent with Mendel's Second law
B.Recombination between homologous chromosomes during meiosis results in different combinations of alleles for different genes
C.Recombination between sister chromatids during meiosis results in different combinations of alleles for different genes

Accepted Answer

A) A only 
B) B only 
C) C only 
D) A and B 
E) A, B, and C

Question 11

Suppose the map for a particular human chromosome interval is: a--1 mu--b--1 mu--c--1 mu--d--1 mu--e--1 mu--f
In a man heterozygous for all six genes, what fraction of his sperm would be recombinant in the a-f interval?

Accepted Answer

A) 0% 
B) 1% 
C) 2.5% 
D) 5% 
E) Cannot be determined

Question 12

In Drosophila, singed bristles (sn) and cut wings (ct) are both caused by recessive, X-linked alleles.The wild type alleles (sn+ and ct+) are responsible for straight bristles and intact wings, respectively.A female homozygous for sn and ct+ is crossed to a sn+ct male.The F1 flies are interbred.The F2 males are distributed as follows  What is the map distance between sn and ct?

Accepted Answer

A) 12 m.u. 
B) 13 m.u. 
C) 25 m.u. 
D) 50 m.u. 
E) 75 m.u.

Question 13

Suppose an individual is heterozygous for a pair of alleles (e.g., A/a).Under what conditions would a crossover in a somatic cell of this individual lead to a clone of cells homozygous for a? (Pick the most precise answer.)

Accepted Answer

A) The crossover would have to occur between the A locus and the centromere and involve two homologous (non-sister) chromatids. 
B) The crossover would have to occur between the A locus and the end of the chromosome and involve two homologous (non-sister) chromatids. 
C) The crossover would have to occur on the same chromosome arm as the A locus and involve two homologous (non-sister) chromatids. 
D) The crossover would have to occur on the same chromosome as the A locus and involve two homologous (non-sister) chromatids. 
E) The crossover would have to occur between the A locus and the centromere and involve two sister chromatids (not homologous) chromatids.

Question 14

his4/TRP1; his4/trp1; HIS4/trp1; HIS4/TRP1

Accepted Answer

A) PD 
B) NPD 
C) T 
D) Cannot be determined

Question 15

Individuals heterozygous for the RB+ and RB- alleles can develop tumors as a result of

Accepted Answer

A) a mitotic crossover that leads to homozygosity for both RB+ and RB-. 
B) a somatic mutation in the RB+ allele that leads to homozygosity for RB-. 
C) a somatic mutation in the RB- allele that leads to homozygosity for RB+. 
D) the fact that RB- is dominant to RB+. 
E) a mitotic crossover that leads to homozygosity for both RB+ and RB- and a somatic mutation in the RB+ allele that leads to homozygosity for RB-.

Question 16

The mother of these progeny resulted from a cross between two flies from true breeding lines.What are the genotypes of these two lines?

Accepted Answer

A) pr pr cn+ cn+ and pr+ pr+ cn cn 
B) pr+ pr+ cn+ cn+ and pr pr cn cn 
C) pr+ pr cn+ cn and pr pr cn cn 
D) pr+ pr cn cn and pr pr cn+ cn 
E) Either pr pr cn+ cn+ and pr+ pr+ cn cn or pr+ pr+ cn+ cn+ and pr pr cn cn could be true.

Question 17

The number of linkage groups in a species that does not have sex chromosomes is:

Accepted Answer

A) 1n 
B) 1n + 1 
C) 2n 
D) 2n + 2

Question 18

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

Accepted Answer

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

Question 19

The number of linkage groups in an organism with sex chromosomes equals:

Accepted Answer

A) 1n 
B) 2n +1 
C) 1n + 1 
D) 2n + 2

Question 20

The length of an entire linkage group or chromosome may exceed 50 mu because the map distance is calculated from the addition of the distance between many gene pairs.

Accepted Answer

A) True 
 B)False

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

In tetrad analysis, NPD asci result from

What is the map distance between the pr and cn genes?

The map of a chromosome interval is: A--10 mu--B--40 mu--C From the cross Abc / aBC * abc / abc, how many double crossovers would be expected out of 1000 progeny?

Crossing over takes place in paired bivalents consisting of chromatids, and involves _ of the chromatids.

What is the $\chi$ ² value for a test of the null hypothesis?

Suppose a three-point testcross was conducted involving the genes X, Y, and Z.If the most abundant classes are XYz and xyZ and the rarest classes are xYZ and Xyz, which gene is in the middle?

What is the coefficient of coincidence in this region?

Calculate the $\chi$ ² value used test the hypothesis that the C and D genes are unlinked.

The cross Lpq / lPQ * lpq / lpq is carried out and the L gene is found to be in the middle.What would be the genotypes of the double crossover gametes in this cross?

Suppose the map for a particular human chromosome interval is: a--1 mu--b--1 mu--c--1 mu--d--1 mu--e--1 mu--f In a man heterozygous for all six genes, what fraction of his sperm would be recombinant in the a-f interval?

Suppose an individual is heterozygous for a pair of alleles (e.g., A/a) .Under what conditions would a crossover in a somatic cell of this individual lead to a clone of cells homozygous for a? (Pick the most precise answer.)

his4/TRP1; his4/trp1; HIS4/trp1; HIS4/TRP1

Individuals heterozygous for the RB⁺ and RB^- alleles can develop tumors as a result of

The mother of these progeny resulted from a cross between two flies from true breeding lines.What are the genotypes of these two lines?

The number of linkage groups in a species that does not have sex chromosomes is:

ws⁺; ws⁺; ws⁺; ws⁺; ws; ws; ws; ws

The number of linkage groups in an organism with sex chromosomes equals:

The length of an entire linkage group or chromosome may exceed 50 mu because the map distance is calculated from the addition of the distance between many gene pairs.

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

In tetrad analysis, NPD asci result from

What is the map distance between the pr and cn genes?

The map of a chromosome interval is: A--10 mu--B--40 mu--C From the cross Abc / aBC * abc / abc, how many double crossovers would be expected out of 1000 progeny?

Crossing over takes place in paired bivalents consisting of ______ chromatids, and involves _______ of the chromatids.

What is the χ \chiχ 2 value for a test of the null hypothesis?

Suppose a three-point testcross was conducted involving the genes X, Y, and Z.If the most abundant classes are XYz and xyZ and the rarest classes are xYZ and Xyz, which gene is in the middle?

What is the coefficient of coincidence in this region?

Calculate the χ \chiχ 2 value used test the hypothesis that the C and D genes are unlinked.

The cross Lpq / lPQ * lpq / lpq is carried out and the L gene is found to be in the middle.What would be the genotypes of the double crossover gametes in this cross?

Suppose the map for a particular human chromosome interval is: a--1 mu--b--1 mu--c--1 mu--d--1 mu--e--1 mu--f In a man heterozygous for all six genes, what fraction of his sperm would be recombinant in the a-f interval?

Suppose an individual is heterozygous for a pair of alleles (e.g., A/a) .Under what conditions would a crossover in a somatic cell of this individual lead to a clone of cells homozygous for a? (Pick the most precise answer.)

his4/TRP1; his4/trp1; HIS4/trp1; HIS4/TRP1

Individuals heterozygous for the RB+ and RB- alleles can develop tumors as a result of

The mother of these progeny resulted from a cross between two flies from true breeding lines.What are the genotypes of these two lines?

The number of linkage groups in a species that does not have sex chromosomes is:

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

The number of linkage groups in an organism with sex chromosomes equals:

The length of an entire linkage group or chromosome may exceed 50 mu because the map distance is calculated from the addition of the distance between many gene pairs.

Crossing over takes place in paired bivalents consisting of chromatids, and involves _ of the chromatids.

What is the $\chi$ ² value for a test of the null hypothesis?

Calculate the $\chi$ ² value used test the hypothesis that the C and D genes are unlinked.

Individuals heterozygous for the RB⁺ and RB^- alleles can develop tumors as a result of

ws⁺; ws⁺; ws⁺; ws⁺; ws; ws; ws; ws