Question 1

Two linked genes, (A) and (B) , are separated by 18 cM.A man with genotype Aa Bb marries a woman who is aa bb.The man's father was AA BB.What is the probability that their first child will be Aa bb?

Accepted Answer

A)  0) 18
B)  0) 41
C)  0) 09
D)  0) 25
E)  0) 50F) A) and B)
G) B) and C)

Question 2

Linked genes:

Accepted Answer

A)  assort randomly.
B)  can't crossover and recombine.
C)  are allelic.
D)  segregate together.
E)  will segregate independently.F) None of the above
G) C) and D)

Question 3

Why are the progeny of a testcross generally used to map loci? Why not the F2 progeny from an F1 × F1 cross?

Accepted Answer

A)  Only recombinant offspring would be found in the progeny of an F1 × F1 cross.
B)  The progeny of an F1 × F1 cross would be found in a 9:3:3:1 ratio when two genes are involved, whereas the progeny of a testcross would result in a 1:1:1:1 ratio.
C)  It is easier to classify recombinant and parental offspring of a testcross than with the progeny of an F1 × F1 cross.
D)  In a testcross more of the progeny would be expected to display the dominant phenotype than in the progeny of an F1 × F1 cross.
E)  A testcross is more useful for mapping genes that are located near each other but when genes are quite far apart on the same chromosome, an F1 × F1 cross actually is more useful.F) A) and B)
G) A) and C)

Question 4

In a two-point linkage analysis, genes a and b have been found to be 26 cM apart on the same chromosome.A third gene, c, has just been discovered and found to be located between a and b.A three-point linkage analysis with a, b, and c indicates that a and b are actually 33 cM apart, rather than 26 cM.Why does the three-point analysis give a different map distance for a and b than does the two-point linkage analysis, and which is more accurate?

Accepted Answer

Multiple crossovers, particularly double...

Question 5

In soreflies (a hypothetical insect) , the dominant allele, L, is responsible for resistance to a common insecticide called Loritol.Another dominant allele, M, is responsible for the ability of soreflies to sing like birds.A true-breeding mute, Loritol-resistant sorefly was mated to a true-breeding singing, Loritol-sensitive sorefly, and the singing, Loritol-resistant female progeny were test-crossed with true-breeding wild type (i.e., mute, Loritol-sensitive) males.Of the 400 total progeny produced, 117 were mute and Loritol-resistant, 114 could sing and were Loritol-sensitive, 83 could sing and were Loritol-resistant, and 86 were mute and Loritol-sensitive.A chi-square test is done to determine if there is equal segregation of alleles at the L locus.What will be the chi-square value obtained and how many degrees of freedom would be used to interpret this value?

Accepted Answer

A)  0) 09 and one degree of freedom
B)  0) 56 and two degrees of freedom
C)  0 and one degree of freedom
D)  9) 72 and four degrees of freedom
E)  A chi-square test is not the appropriate statistical test to answer this question.F) C) and D)
G) All of the above

Question 6

An individual has the following genotype.Gene loci (A) and (B) are 15 cM apart.What are the CORRECT frequencies of some of the gametes that can be made by this individual?

Accepted Answer

A)  Ab = 7.5%; AB = 42.5%
B)  ab = 25%; aB = 50%
C)  AB = 7.5%; aB = 42.5%
D)  aB = 15%; Ab = 70%
E)  aB = 70%; Ab = 15%F) A) and B)
G) C) and E)

Question 7

A single nucleotide polymorphism can be associated with a disease trait based on its genetic _____ to that trait.

Accepted Answer

A)  linkage
B)  lod
C)  uniqueness
D)  recombination distance
E)  phenotypeF) C) and D)
G) B) and E)

Question 8

Consider the following three-point (trihybrid) testcross:  Calculate the number of double crossovers you would expect to observe if 1000 progeny result from this testcross assuming a coefficient of coincidence of 0.25.

Accepted Answer

A)  About 14
B)  About 26
C)  About 10
D)  About 4
E)  None, because there is crossover interferenceF) All of the above
G) C) and D)

Question 9

Linked genes are:

Accepted Answer

A)  allelic.
B)  dominant.
C)  on different chromosomes.
D)  on the same chromosome.
E)  recessive lethal.F) B) and C)
G) A) and E)

Question 10

A genetic map shows which of the following?

Accepted Answer

A)  The distance in numbers of nucleotides between two genes
B)  The number of genes on each of the chromosomes of a species
C)  The linear order of genes on a chromosome
D)  The location of chromosomes in the nucleus when they line up at metaphase during mitosis
E)  The location of double crossovers that occur between two genesF) A) and E)
G) C) and E)

Question 11

You just bought two black guinea pigs, one male and one female, of the same genotype from the pet store that are known to be heterozygous (Bb) .You also know that black fur (BB) is dominant over white fur (bb) , and that a lethal recessive allele is located only one cM away from the recessive b allele and your animals are both heterozygous for this gene also.You decide to start raising your own guinea pigs, but after mating these animals several times, you discover they produce only black offspring among the first 12 progeny.How would you BEST explain this result?

Accepted Answer

A)  The B locus is on the X chromosome, so it can never produce a white phenotype.
B)  The B allele is actually codominant with the b allele, so a white phenotype cannot be produced.
C)  The recessive lethal allele is in tight coupling linkage with the b allele, so almost all of the bb offspring will also be ll and thus die before they can be observed.
D)  The dominant L allele is in tight repulsion linkage with the B allele, so it will be impossible to produce the Bb genotype that would express the white phenotype.
E)  Normally, it would be expected that 25% of the offspring would be white, but in this case, random deviations resulted in no white offspring.F) A) and C)
G) None of the above

Question 12

In corn, small pollen (sp) is recessive to normal pollen (sp+) and banded necrotic tissue, called zebra necrotic (zn) , is recessive to normal tissue (zn+) .The genes that produce these phenotypes are closely linked on chromosome 10.If no crossing over occurs between these two loci, give the types of progeny expected from the following cross: +) and banded necrotic tissue, called zebra necrotic (zn) , is recessive to normal tissue (zn+) .The genes that produce these phenotypes are closely linked on chromosome 10.If no crossing over occurs between these two loci, give the types of progeny expected from the following cross:   A) sp+ zn+/sp zn; sp zn/sp zn B) sp+ zn/sp zn; sp zn+/sp zn C) sp+ zn+/sp+ zn+; sp+ zn+/sp zn; sp zn/sp zn D) sp+ zn/sp+ zn; sp+ zn/sp zn+; sp zn+/sp+ zn; sp zn+/sp zn+ E) sp+ zn+/sp zn; sp+ zn/sp zn" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  sp+ zn+/sp zn; sp zn/sp zn
B)  sp+ zn/sp zn; sp zn+/sp zn
C)  sp+ zn+/sp+ zn+; sp+ zn+/sp zn; sp zn/sp zn
D)  sp+ zn/sp+ zn; sp+ zn/sp zn+; sp zn+/sp+ zn; sp zn+/sp zn+
E)  sp+ zn+/sp zn; sp+ zn/sp znF) A) and B)
G) B) and C)

Question 13

Compared to a physical map, a genetic map:

Accepted Answer

A)  is more accurate.
B)  is less accurate.
C)  is equally accurate.
D)  measures recombinant distance between genes.
E)  cannot be made for humans.F) B) and C)
G) D) and E)

Question 14

Consider the following three-factor (trihybrid) testcross: +a bb c+c genotype if 1000 progeny result from this testcross. A) About 102 B) About 46 C) About 130 D) About 65 E) About 250" class="answers-bank-image d-inline" rel="preload" > Calculate the number of expected individuals of a+a bb c+c genotype if 1000 progeny result from this testcross.

Accepted Answer

A)  About 102
B)  About 46
C)  About 130
D)  About 65
E)  About 250F) A) and D)
G) None of the above

Question 15

Recombination occurs through:

Accepted Answer

A)  crossing over and chromosome interference.
B)  chromosome interference and independent assortment.
C)  somatic-cell hybridization and chromosome interference.
D)  complete linkage and chromosome interference.
E)  crossing over and independent assortment.F) A) and C)
G) B) and D)

Question 16

A low coefficient of coincidence indicates that:

Accepted Answer

A)  far fewer double crossover recombinant progeny were recovered from a testcross than would be expected from the map distances of the genes involved.
B)  crossing over has been enhanced for genes that are located near the centromere of chromosomes because there is less interference of one crossover on the occurrence of a second crossover event.
C)  single crossover recombinant classes in the progeny have been increased because the genes involved produce lethal phenotypes when in parental gene combinations.
D)  there is a large map distance between one of the outside genes in the heterozygous parent and the middle gene, while there is a short map distance between the middle gene and the other outside gene.
E)  the physical distance between two genes is very short compared with the genetic map distance between these two genes.F) A) and B)
G) B) and C)

Question 17

How is chi-square test used to test genetic recombination, and what does it tell you?

Accepted Answer

The chi-square test is a statistical too...

Question 18

Discuss the differences, and at least one similarity, between recombination and independent assortment.

Accepted Answer

Genetic recombination (i.e., recombinati...

Question 19

You are doing lab work with a new species of beetle.You isolated lines that breed true for either blue shells and long antenna, or green shells and short antenna.Crossing these lines yields F1 progeny with blue shells and long antenna.Crossing F1 progeny with beetles that have green shells and short antenna yield the following progeny: 1 progeny with blue shells and long antenna.Crossing F1 progeny with beetles that have green shells and short antenna yield the following progeny:   Assuming that the genes are linked, what is the map distance in cM between them? A) 33.3 cM B) 25.0 cM C) 49.5 cM D) 8) 0 cM E) The genes are actually assorting independently." class="answers-bank-image d-inline" rel="preload" > Assuming that the genes are linked, what is the map distance in cM between them?

Accepted Answer

A)  33.3 cM
B)  25.0 cM
C)  49.5 cM
D)  8) 0 cM
E)  The genes are actually assorting independently.F) A) and D)
G) A) and E)

Question 20

A series of two-point crosses among fruit flies is carried out between genes for brown eyes (bw) , arc wings (a) , vestigial wings (vg) , ebony body color (e) , and curved wings (cv) .The following number of nonrecombinant and recombinant progeny were obtained from each cross:  Using these data from two-point crosses, what it the BEST genetic map (in cM) that can be developed?

Accepted Answer

A)  cv 5 bw 13 a 34 vg with e assorting independently
B)  bw 5 cv 24 vg 32 a with e assorting independently
C)  a 5 bw 13 vg 24 e with vg assorting independently
D)  cv 13 bw 5 a 27 vg with e assorting independently
E)  bw 5 a 24 cv 13 vg with e assorting independentlyF) B) and E)
G) A) and B)

Exam 5: Linkage, Recombination, and Eukaryotic Gene Mapping

Recombination occurs through:

Correct Answer
verified

Compared to a physical map, a genetic map:

Correct Answer
verified

Correct Answer
verified

Why are the progeny of a testcross generally used to map loci? Why not the F₂ progeny from an F₁ × F₁ cross?

Correct Answer
verified

A genetic map shows which of the following?

Correct Answer
verified

Two linked genes, (A) and (B) , are separated by 18 cM.A man with genotype Aa Bb marries a woman who is aa bb.The man's father was AA BB.What is the probability that their first child will be Aa bb?

Correct Answer
verified

Correct Answer
verified

Linked genes:

Correct Answer
verified

Correct Answer
verified

How is chi-square test used to test genetic recombination, and what does it tell you?

Correct Answer
verified
The chi-square test is a statistical too...
View Answer

Correct Answer
verified

A single nucleotide polymorphism can be associated with a disease trait based on its genetic _____ to that trait.

Correct Answer
verified

Consider the following three-point (trihybrid) testcross: Calculate the number of double crossovers you would expect to observe if 1000 progeny result from this testcross assuming a coefficient of coincidence of 0.25.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Multiple crossovers, particularly double...
View Answer

Discuss the differences, and at least one similarity, between recombination and independent assortment.

Correct Answer
verified
Genetic recombination (i.e., recombinati...
View Answer

A low coefficient of coincidence indicates that:

Correct Answer
verified

Linked genes are:

Correct Answer
verified

An individual has the following genotype.Gene loci (A) and (B) are 15 cM apart.What are the CORRECT frequencies of some of the gametes that can be made by this individual?

Correct Answer
verified

Consider the following three-factor (trihybrid) testcross: Calculate the number of expected individuals of a⁺a bb c⁺c genotype if 1000 progeny result from this testcross.

Correct Answer
verified

Exam 5: Linkage, Recombination, and Eukaryotic Gene Mapping

Recombination occurs through:

Correct AnswerverifiedShow Answer

Compared to a physical map, a genetic map:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Why are the progeny of a testcross generally used to map loci? Why not the F2 progeny from an F1 × F1 cross?

Correct AnswerverifiedShow Answer

A genetic map shows which of the following?

Correct AnswerverifiedShow Answer

Two linked genes, (A) and (B) , are separated by 18 cM.A man with genotype Aa Bb marries a woman who is aa bb.The man's father was AA BB.What is the probability that their first child will be Aa bb?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Linked genes:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

How is chi-square test used to test genetic recombination, and what does it tell you?

Correct AnswerverifiedThe chi-square test is a statistical too...View AnswerShow Answer

Correct AnswerverifiedShow Answer

A single nucleotide polymorphism can be associated with a disease trait based on its genetic _____ to that trait.

Correct AnswerverifiedShow Answer

Consider the following three-point (trihybrid) testcross: Calculate the number of double crossovers you would expect to observe if 1000 progeny result from this testcross assuming a coefficient of coincidence of 0.25.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedMultiple crossovers, particularly double...View AnswerShow Answer

Discuss the differences, and at least one similarity, between recombination and independent assortment.

Correct AnswerverifiedGenetic recombination (i.e., recombinati...View AnswerShow Answer

A low coefficient of coincidence indicates that:

Correct AnswerverifiedShow Answer

Linked genes are:

Correct AnswerverifiedShow Answer

An individual has the following genotype.Gene loci (A) and (B) are 15 cM apart.What are the CORRECT frequencies of some of the gametes that can be made by this individual?

Correct AnswerverifiedShow Answer

Consider the following three-factor (trihybrid) testcross: Calculate the number of expected individuals of a+a bb c+c genotype if 1000 progeny result from this testcross.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Why are the progeny of a testcross generally used to map loci? Why not the F₂ progeny from an F₁ × F₁ cross?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The chi-square test is a statistical too...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Multiple crossovers, particularly double...
View Answer

Correct Answer
verified
Genetic recombination (i.e., recombinati...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Consider the following three-factor (trihybrid) testcross: Calculate the number of expected individuals of a⁺a bb c⁺c genotype if 1000 progeny result from this testcross.

Correct Answer
verified