Question 1

In fruit flies, red eyes (pr+_) are dominant to purple eyes (prpr) and normal wings (vg+_) are dominant to vestigial wings (vgvg) . The genes are located on the same chromosome. A purebreeding red-eyed fly with vestigial wings was crossed with a pure-breeding purple-eyed fly with normal wings. All of the F1 progeny had a WT phenotype. Which of the following represents the arrangement of alleles on the F1's chromosome?

Accepted Answer

A)  prvg/pr+vg+
B)  pr+vg/prvg+
C)  prpr+/vgvg+
D)  prvg/prvg
E)  pr+vg+/pr+vg+

Question 2

Crossing over occurs frequently during meiosis. Can crossing over occur during mitosis? Explain why mitotic crossing over may or may not be possible.

Accepted Answer

Mitotic crossover is a rare event. Mitot...

Question 3

In a two-point test-cross analysis, a dihybrid F1 fly is crossed to a __________.

Accepted Answer

A)  pure-breeding mate with a dominant phenotype (AAB
B)  
B)  pure-breeding mate with a recessive phenotype (aabb) 
C)  heterozygote mate (AaBb) 
D)  mate that is dominant for one gene and recessive for the other (AAbb or aaB
B)  
E)  second dihybrid F1 fly (sibling cross)

Question 4

A chromosome with a different combination of alleles than parental that is created by crossing over between homologous chromosomes is termed ________.

Accepted Answer

recombinan...

Question 5

Which type of crossover event produces no recombinant chromosomes?

Accepted Answer

A)  single-strand crossover
B)  two-strand double crossover
C)  three-strand double crossover
D)  four-strand double crossover
E)  None of the above; all crossover events produce recombinant chromosomes.

Question 6

Alleles of linked genes usually segregate together during meiosis. When they don't, it is because ________ has occurred between them.

Accepted Answer

The answer of Alleles of linked genes usually segregate together...

Question 7

Two genes, A and X, exhibit incomplete linkage. The frequency of each parental gamete (AX and ax)is 45%. What is the approximate frequency of the Ax gamete?

Accepted Answer

The answer of Two genes, A and X, exhibit incomplete...

Question 8

Genetic linkage can be spotted by comparing the observed frequencies of ________ with the frequencies expected (assuming independent assortment).

Accepted Answer

gamete gen...

Question 9

What unit of physical distance between genes on a chromosome provides a convenient way to relate the recombination frequencies for linked genes with their positions and order along a chromosome?

Accepted Answer

map unit (...

Question 10

Intragenic recombination can be detected __________.

Accepted Answer

A)  based on recombination between homologs carrying different mutant alleles
B)  by the recovery of 100% double-mutant chromosomes
C)  by the recovery of both wild-type and double-mutant chromosomes
D)  based on recombination between homologs with different mutant alleles and recovery of 100% double-mutant chromosomes
E)  based on recombination between homologs with different mutant alleles and recovery of both wild-type and double-mutant chromosomes

Question 11

Where does crossing over occur?

Accepted Answer

A)  at the centromeres
B)  at the telomeres
C)  at nodules that occur randomly at "hotspots" along the synaptonemal complex
D)  at nodules that occur in specific, evenly spaced locations along a chromosome
E)  at both the centromeres and telomeres

Question 12

5% recombination is equal to ________ map unit(s)(m.u.)or centimorgan(s)(cM)of distance between linked genes.

Accepted Answer

The answer of 5% recombination is equal to ________ map...

Question 13

Genetic linkage leads to the production of a significantly greater than expected number of gametes containing chromosomes with __________.

Accepted Answer

A)  allele combinations that are different from parental combinations
B)  parental combinations of alleles
C)  mutant alleles
D)  dominant alleles
E)  recessive alleles

Question 14

When does recombination occur?

Accepted Answer

A)  before DNA replication
B)  at the two-strand stage, when each member of a homologous chromosome pair is composed of two sister chromatids, and before DNA replication
C)  at the four-strand stage, when each member of a homologous chromosome pair is composed of two sister chromatids, and before DNA replication
D)  at the two-strand stage, when the sister chromatids have been separated, and after DNA replication
E)  at the four-strand stage, when each member of a homologous chromosome pair is composed of two sister chromatids, and after DNA replication

Question 15

The products of meiosis yield the following results:
PD = 1200 TT = 750 NPD = 50
What is the recombination frequency?

Accepted Answer

RF = [(NPD + 1/2TT)/...

Question 16

The specific array of alleles making up a set of linked genes on a single chromosome is called a ________.

Accepted Answer

The answer of The specific array of alleles making up...

Question 17

If too little time has passed for crossing over to randomize haplotypes or if natural selection favors certain haplotypes, what would you expect to see?

Accepted Answer

linkage di...

Question 18

If you are given a recombination frequency of 34% between genes X and Y and 27% between X and Z, can you predict the order of the three genes?

Accepted Answer

A)  Yes; the order is X-Z-Y.
B)  Yes; the order is X-Y-Z.
C)  Yes; the order is Z-X-Y.
D)  No; based on this data alone, the order could be Z-Y-X or X-Y-Z.
E)  No; based on this data alone, the order could be X-Z-Y or Z-X-Y.

Question 19

The syntenic genes A and Z are linked. A cross between two parents, AAZZ and aazz, produces F1 progeny with the AaZz genotype. What are the possible arrangements of alleles on the F1 progeny's chromosomes?

Accepted Answer

A)  AZ/az
B)  Az/aZ
C)  Aa/Zz
D)  AZ/Az or az/aZ
E)  A/Z or a/z

Question 20

In most tests of genetic linkage, the number of double crossovers is less than the number expected due to what effect, which limits the number of crossovers that can occur in a short length of chromosome?

Accepted Answer

The answer of In most tests of genetic linkage, the...

Exam 5: Genetic Linkage and Mapping in Eukaryotes

Crossing over occurs frequently during meiosis. Can crossing over occur during mitosis? Explain why mitotic crossing over may or may not be possible.

Correct Answer
verified
Mitotic crossover is a rare event. Mitot...
View Answer

Genetic linkage leads to the production of a significantly greater than expected number of gametes containing chromosomes with __________.

Correct Answer
verified

Genetic linkage can be spotted by comparing the observed frequencies of ________ with the frequencies expected (assuming independent assortment).

Correct Answer
verified
gamete gen...
View Answer

The specific array of alleles making up a set of linked genes on a single chromosome is called a ________.

Correct Answer
verified

Two genes, A and X, exhibit incomplete linkage. The frequency of each parental gamete (AX and ax)is 45%. What is the approximate frequency of the Ax gamete?

Correct Answer
verified

Intragenic recombination can be detected __________.

Correct Answer
verified

When does recombination occur?

Correct Answer
verified

A chromosome with a different combination of alleles than parental that is created by crossing over between homologous chromosomes is termed ________.

Correct Answer
verified
recombinan...
View Answer

In most tests of genetic linkage, the number of double crossovers is less than the number expected due to what effect, which limits the number of crossovers that can occur in a short length of chromosome?

Correct Answer
verified

What unit of physical distance between genes on a chromosome provides a convenient way to relate the recombination frequencies for linked genes with their positions and order along a chromosome?

Correct Answer
verified
map unit (...
View Answer

Correct Answer
verified

If too little time has passed for crossing over to randomize haplotypes or if natural selection favors certain haplotypes, what would you expect to see?

Correct Answer
verified
linkage di...
View Answer

If you are given a recombination frequency of 34% between genes X and Y and 27% between X and Z, can you predict the order of the three genes?

Correct Answer
verified

In a two-point test-cross analysis, a dihybrid F₁ fly is crossed to a __________.

Correct Answer
verified

Alleles of linked genes usually segregate together during meiosis. When they don't, it is because ________ has occurred between them.

Correct Answer
verified

Where does crossing over occur?

Correct Answer
verified

The syntenic genes A and Z are linked. A cross between two parents, AAZZ and aazz, produces F₁ progeny with the AaZz genotype. What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

Correct Answer
verified

5% recombination is equal to ________ map unit(s)(m.u.)or centimorgan(s)(cM)of distance between linked genes.

Correct Answer
verified

Which type of crossover event produces no recombinant chromosomes?

Correct Answer
verified

The products of meiosis yield the following results: PD = 1200 TT = 750 NPD = 50 What is the recombination frequency?

Correct Answer
verified
RF = [(NPD + 1/2TT)/...
View Answer

Exam 5: Genetic Linkage and Mapping in Eukaryotes

Crossing over occurs frequently during meiosis. Can crossing over occur during mitosis? Explain why mitotic crossing over may or may not be possible.

Correct AnswerverifiedMitotic crossover is a rare event. Mitot...View AnswerShow Answer

Genetic linkage leads to the production of a significantly greater than expected number of gametes containing chromosomes with __________.

Correct AnswerverifiedShow Answer

Genetic linkage can be spotted by comparing the observed frequencies of ________ with the frequencies expected (assuming independent assortment).

Correct Answerverifiedgamete gen...View AnswerShow Answer

The specific array of alleles making up a set of linked genes on a single chromosome is called a ________.

Correct AnswerverifiedShow Answer

Two genes, A and X, exhibit incomplete linkage. The frequency of each parental gamete (AX and ax)is 45%. What is the approximate frequency of the Ax gamete?

Correct AnswerverifiedShow Answer

Intragenic recombination can be detected __________.

Correct AnswerverifiedShow Answer

When does recombination occur?

Correct AnswerverifiedShow Answer

A chromosome with a different combination of alleles than parental that is created by crossing over between homologous chromosomes is termed ________.

Correct Answerverifiedrecombinan...View AnswerShow Answer

In most tests of genetic linkage, the number of double crossovers is less than the number expected due to what effect, which limits the number of crossovers that can occur in a short length of chromosome?

Correct AnswerverifiedShow Answer

What unit of physical distance between genes on a chromosome provides a convenient way to relate the recombination frequencies for linked genes with their positions and order along a chromosome?

Correct Answerverifiedmap unit (...View AnswerShow Answer

Correct AnswerverifiedShow Answer

If too little time has passed for crossing over to randomize haplotypes or if natural selection favors certain haplotypes, what would you expect to see?

Correct Answerverifiedlinkage di...View AnswerShow Answer

If you are given a recombination frequency of 34% between genes X and Y and 27% between X and Z, can you predict the order of the three genes?

Correct AnswerverifiedShow Answer

In a two-point test-cross analysis, a dihybrid F1 fly is crossed to a __________.

Correct AnswerverifiedShow Answer

Alleles of linked genes usually segregate together during meiosis. When they don't, it is because ________ has occurred between them.

Correct AnswerverifiedShow Answer

Where does crossing over occur?

Correct AnswerverifiedShow Answer

The syntenic genes A and Z are linked. A cross between two parents, AAZZ and aazz, produces F1 progeny with the AaZz genotype. What are the possible arrangements of alleles on the F1 progeny's chromosomes?

Correct AnswerverifiedShow Answer

5% recombination is equal to ________ map unit(s)(m.u.)or centimorgan(s)(cM)of distance between linked genes.

Correct AnswerverifiedShow Answer

Which type of crossover event produces no recombinant chromosomes?

Correct AnswerverifiedShow Answer

The products of meiosis yield the following results: PD = 1200 TT = 750 NPD = 50 What is the recombination frequency?

Correct AnswerverifiedRF = [(NPD + 1/2TT)/...View AnswerShow Answer

Correct Answer
verified
Mitotic crossover is a rare event. Mitot...
View Answer

Correct Answer
verified

Correct Answer
verified
gamete gen...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
recombinan...
View Answer

Correct Answer
verified

Correct Answer
verified
map unit (...
View Answer

Correct Answer
verified

Correct Answer
verified
linkage di...
View Answer

Correct Answer
verified

In a two-point test-cross analysis, a dihybrid F₁ fly is crossed to a __________.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The syntenic genes A and Z are linked. A cross between two parents, AAZZ and aazz, produces F₁ progeny with the AaZz genotype. What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
RF = [(NPD + 1/2TT)/...
View Answer