Q: If two A\^Y A mice are crossed, what is the expected phenotypic ratio among the surviving offspring?

$$2:1$$ \text{ yellow to agouti}$

Q: A cross between an A\^Y a mouse and an Aa mouse produces which phenotypic ratio for coat color?

$$2 \text{ yellow}: 1 \text{ agouti}: 1 \text{ black}$$

Q: What is the expected F2 phenotypic ratio for coat color in a cross between two F1 agouti mice (AaBb x AaBb)?

$$9:3:4$$ \text{ agouti: albino: black}$

Question 1

Which of the following best describes the inheritance pattern of the A\^Y allele in mice?

Accepted Answer

A\^Y is dominant for coat color but recessive for lethality.

Question 2

If two A\^Y A mice are crossed, what is the expected phenotypic ratio among the surviving offspring?

Accepted Answer

$$2:1$$ 	ext{ yellow to agouti}$

Question 3

Why do A\^Y A\^Y mice die before birth?

Accepted Answer

Because the A\^Y allele deletes the regulatory region of the agouti gene and part of the adjacent Merc gene, causing lethality when both copies are affected.

Question 4

Which genotype results in a solid black coat color in mice?

Accepted Answer

$$aa$$

Question 5

A cross between an A\^Y a mouse and an Aa mouse produces which phenotypic ratio for coat color?

Accepted Answer

$$2 	ext{ yellow}: 1 	ext{ agouti}: 1 	ext{ black}$$

Question 6

Which of the following best defines epistasis?

Accepted Answer

When the expression of one gene masks or modifies the expression of another gene.

Question 7

In mouse coat color genetics, which locus is epistatic to the Agouti locus?

Accepted Answer

B locus

Question 8

What is the expected F2 phenotypic ratio for coat color in a cross between two F1 agouti mice (AaBb x AaBb)?

Accepted Answer

$$9:3:4$$ 	ext{ agouti: albino: black}$

Question 9

Which F2 genotype from an AaBb x AaBb cross will result in an albino mouse?

Accepted Answer

$$bb$$ 	ext{ homozygotes}$

Question 10

If two genes are 1 centiMorgan (cM) apart on a chromosome, what is the probability that alleles for these genes will NOT be inherited together?

Accepted Answer

$$1\%$$

Question 11

Which of the following statements about genetic linkage is correct?

Accepted Answer

Linked genes are more likely to be inherited together than to segregate independently.

Question 12

A cross between an A\^Y aBb mouse and an Aabb mouse is performed. Using the product law, what is the expected ratio of albino offspring?

Accepted Answer

$$1/4$$

Question 13

Which of the following is a real-world example of epistasis?

Accepted Answer

The Bombay phenotype in human ABO blood groups.

Question 14

If two genes are not linked, what is the probability that alleles for these genes will be inherited together?

Accepted Answer

$$50\%$$

Question 15

Which of the following best explains why bb homozygotes in mice have an albino coat?

Accepted Answer

The B locus is required for pigment production; without it, no color is produced regardless of the Agouti locus.

Question 16

Which of the following is true regarding the modified 9:3:4 ratio observed in mouse coat color genetics?

Accepted Answer

It is a result of epistasis, where one gene masks the effect of another.

Question 17

Which of the following scenarios would most likely result in genetic linkage?

Accepted Answer

Two genes located close together on the same chromosome.

Question 18

A researcher observes that two genes have a recombination frequency of 1%. What is the most likely distance between these genes?

Accepted Answer

$$1 	ext{ cM}$$

Question 19

Which of the following is NOT a consequence of a 120,000 nucleotide deletion in the A\^Y allele?

Accepted Answer

Increased expression of the B locus.

Question 20

Which of the following crosses would produce a 9:3:4 ratio in the F2 generation for mouse coat color?

Accepted Answer

AaBb x AaBb

Genetics Study Notes- Sep 10

Study Guide - Practice Questions

Study Guide - Flashcards