Question 1

What is the map distance between the pr and cn genes?
A)20 m.u.
B)2 m.u.
C)4 m.u.
D)46 m.u.
E)8 m.u.

Accepted Answer

The answer of What is the map distance between the...

Question 2

What is the p value from this test? (Pick the most accurate choice.)
A)p > 0.5
B)0.1 < p < 0.5
C)p < 0.1
D)p < 0.05
E)p < 0.01

Accepted Answer

The answer of What is the p value from this...

Question 3

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

Accepted Answer

A crossover can occur between homologous chromosomes during meiosis which results in exchange of genetic material. This exchange happens between non-sister chromatids. Therefore, the only options that allow for this exchange are 1 & 3, 1 & 4, 2 & 3, or 2 & 4. Thus, Option D (1 & 3 or 1 & 4 or 2 & 3 or 2 & 4) is the best choice.

Question 4

What is the $ \chi$² value for a test of the null hypothesis? A)0.5 B)1.0 C)2.0 D)0.4 E)20

Accepted Answer

The $ \chi $² value for a test of the null hypothesis is 2.0. This is because the $ \chi $² distribution is a chi-squared distribution with 1 degree of freedom, and the critical value for a test of the null hypothesis at the 0.05 level of significance is 2.0.

Question 5

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

Accepted Answer

The answer of The mother of these progeny resulted from...

Question 6

What is the genotype of the mother of these progeny? A)pr cn / pr⁺ cn⁺ B)pr⁺ cn / pr⁺ cn C)pr⁺ cn / pr cn⁺ D)pr cn⁺/ pr cn⁺ E)pr cn / pr cn

Accepted Answer

The progeny shows a combination of alleles that can only be explained if the mother has one pr+ cn and one pr cn+ allele, allowing for recombination to produce the observed offspring genotypes.

Question 7

Which of the following types of tetrads contain two recombinant and two parental asci?
A)PD only
B)PD and NPD
C)T only
D)PD and T
E)NPD and T

Accepted Answer

Tetrads that contain two recombinant and two parental asci are called tetratype (T) asci.

Question 8

Which classes are the parental types?
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.

Accepted Answer

The answer of Which classes are the parental types?
A)wild-type and...

Question 9

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?
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.

Accepted Answer

The answer of If an individual is heterozygous at two...

Question 10

his4/TRP1; his4/TRP1; HIS4/trp1; HIS4/trp1
A)PD
B)NPD
C)T
D)Cannot be determined

Accepted Answer

NPD: Non-parental ditype

Question 11

HIS4/trp1; HIS4/trp1; his4/TRP1; his4/TRP1
A)PD
B)NPD
C)T
D)Cannot be determined

Accepted Answer

NPD (non-parental ditype)

Question 12

What happens physically during the process of crossing over?
A)Two homologous chromatids break and rejoin at random sites along the chromosome.
B)The genetic information on one chromatid is replaced by copying genetic information from a homologous chromatid without there being any physical exchange between the chromosomes.
C)Two homologous chromatids break and rejoin at precisely the same site along the chromosome so that there is no loss or gain of material on either product.
D)It is not known what occurs during crossing over.

Accepted Answer

During crossing over, homologous chromatids break and rejoin at the same site, allowing for the exchange of genetic material without loss or gain.

Question 13

A woman whose mother is colorblind and whose father has hemophilia A is pregnant with a boy and what is the probability that the baby will have normal vision and blood clotting?
A)0.03
B)0.15
C)0.485
D)0.47
E)0.015

Accepted Answer

The answer of A woman whose mother is colorblind and...

Question 14

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

Accepted Answer

Since two of the woman's sons have hemophilia (an X-linked recessive trait) and two have normal clotting, it is most likely that the woman is a carrier of the hemophilia allele on one of her X chromosomes and has a normal clotting allele on her other X chromosome. This would result in a genotype of Hr/hR, which could produce both hemophiliac and non-hemophiliac offspring depending on which X chromosome is passed on to each son. The fact that two of her sons are colorblind (another X-linked trait) suggests that the woman may also be a carrier of the color blindness allele on one of her X chromosomes, but this information is not necessary for determining her probable genotype.

Question 15

his4/TRP1; his4/trp1; HIS4/trp1; HIS4/TRP1
A)PD
B)NPD
C)T
D)Cannot be determined

Accepted Answer

HIS4 and TRP1 are two different genes that encode for enzymes involved in the biosynthesis of histidine and tryptophan, respectively.

In the genotype notation, a slash (/) or a semicolon (;) is used to separate the alleles from different genes. In this case, the first letter refers to the allele of one gene and the second letter refers to the allele of the other gene.

Since HIS4/TRP1 and HIS4/trp1 both have at least one functional allele of each gene, they are both prototrophic (able to grow on minimal media lacking histidine and tryptophan).

On the other hand, his4/trp1 has mutations in both genes and is therefore unable to synthesize either histidine or tryptophan. It is therefore auxotrophic (unable to grow on minimal media lacking histidine and tryptophan).

Lastly, HIS4/TRP1 specifies that both genes are on the same chromosome, while the other genotypes do not provide information about chromosomal location.

Question 16

HIS4/trp1; HIS4/TRP1; his4/TRP1; his4/trp1
A)PD
B)NPD
C)T
D)Cannot be determined

Accepted Answer

Since HIS4 and TRP1 are located on different chromosomes, the alleles are unlinked and thus undergo independent assortment during meiosis. Therefore, the genotype of one locus is not affected by the genotype of the other locus. This means that the genotypes HIS4/trp1, HIS4/TRP1, his4/TRP1, and his4/trp1 are all possible and equally likely, resulting in a test cross ratio of 1:1:1:1. Therefore, the offspring of a cross between two individuals with these genotypes would show a classic Mendelian pattern of segregation and be able to undergo independent assortment. Thus, this scenario would be considered a true classic Mendelian test cross and would result in a 1:1:1:1 ratio of genotypes.

Question 17

his4/trp1; his4/trp1; HIS4/TRP1;HIS4/TRP
A)PD
B)NPD
C)T
D)Cannot be determined

Accepted Answer

The answer of his4/trp1; his4/trp1; HIS4/TRP1;HIS4/TRP
A)PD
B)NPD
C)T
D)Cannot be determined...

Question 18

Some of the larger human chromosomes typically contain multiple chiasmata during meiotic prophase.If you were to carefully study the distribution of these chiasmata, what would you find?
A)Chiasmata are randomly distributed along chromosomes.
B)All chromosome pairs have the same number of chiasmata.
C)A single chromosome pair always has the same number of chiasmata in every meiotic cell.
D)Chiasmata are spaced along a chromosome arm more regularly than would be expected by chance.
E)Chiasmata are spaced more irregularly along a chromosome arm than would be expected by chance.

Accepted Answer

Chiasmata are spaced along a chromosome arm more regularly than would be expected by chance to ensure proper segregation of homologous chromosomes during meiosis.

Question 19

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

Accepted Answer

The answer of Individuals heterozygous for the RB⁺ and RB^-...

Question 20

Assume a double crossover occurs in this pair of chromosomes that results in chromatids of the genotype AbC and aBc.If the first crossover (the one between A and B) involves chromatids 1 & 4, which chromatids could be involved in the second crossover?
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

Accepted Answer

The answer of Assume a double crossover occurs in this...

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

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

What is the p value from this test? (Pick the most accurate choice.)

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

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

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

What is the genotype of the mother of these progeny?

Which of the following types of tetrads contain two recombinant and two parental asci?

Which classes are the parental types?

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?

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

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

What happens physically during the process of crossing over?

A woman whose mother is colorblind and whose father has hemophilia A is pregnant with a boy and what is the probability that the baby will have normal vision and blood clotting?

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?

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

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

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

Some of the larger human chromosomes typically contain multiple chiasmata during meiotic prophase.If you were to carefully study the distribution of these chiasmata, what would you find?

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

Assume a double crossover occurs in this pair of chromosomes that results in chromatids of the genotype AbC and aBc.If the first crossover (the one between A and B) involves chromatids 1 & 4, which chromatids could be involved in the second crossover?