Question

1) (3 pts) Short hair in rabbits is governed by a dominant allele L and long hair by its recessive allele, l. Black hair results from the action of the dominant genotype B- and brown from the recessive genotype bb.

a) What are the gametes possible from a doe (female rabbit) with the genotype Llbb?

b) Depict the associated Punnett square or branch diagram for the cross: LlBb x LLBb

2) (6 pts) A dominant sex-linked allele B controls silver-colored plumage in poultry, and the alternative recessive allele (b) results in gold-colored plumage. Use alleles “B” and “b” to answer the following:

1. a) Using appropriate symbols, determine the genotypic and phenotypic ratios expected in the offspring from the cross: silver female x gold male.

2. b) If the male and female offspring from (a) are mated, what would be the expected genotypic and phenotypic ratios of the offspring?

Updated: 1-17-2020 Concept Challenge Questions 3: ANS 314 Page 1 of 2

3)

(6 pts) Sean is a cat breeder, and he set up a mating of two white cats expecting all the kittens to be white. To his surprise, the litter had two tabby and one solid black kitten. [Note: Tabby is black striped, not tortoiseshell; tabby is autosomal dominant.] The same mating was repeated, and the litter included tabby, black and white kittens. Sean decided to call his niece who was taking ANS 314 at MSU to help him understand these color patterns. His niece suggested that the colors of the kittens might result from two interacting loci, and that the two white parents might each carry a dominant color-suppressing allele. Perhaps when the white cats were mated, non-suppressing alleles had segregated to some of the kittens resulting in tabby and black colors. Let (R) represent the color suppressing allele, and (r) represent the color allele with R > r. Tabby is controlled by (T) and black by (t) with T > t.

1. a) Based on these observations, what is the mode of interaction/inheritance for the W and T loci?

2. b) What phenotypic ratio would be expected if cats heterozygous at locus R and homozygous recessive at locus T were mated to dihybrid cats?

Answer 1

1) a) genotype of the rabbit of Llbb, it is heterozygous at one locus so the number of possible gametes 2^number of heterozygous locus=2^1=2

possible gametes are Lb and lb.

b) LlBb * LLBb

	LB	Lb	lB	lb
LB	LLBB (long, black hair)	LLBb(long, black hair)	LlBB(long, black hair)	LlBb(long, black hair)
Lb	LLBb (long, black hair)	LLbb (long brown hair)	LlBb(long, black hair)	Llbb (long brown hair)