## Q6. In mice, the allele for black hair color is (B) dominant to that for brown (b), the allele for short hair (H) is dominant to that f

Question

Q6. In mice, the allele for black hair color is (B) dominant to that for brown (b), the allele for
short hair (H) is dominant to that for long hair (h). The gene for hair color and length are not
linked (i.e. they are on separate chromosomes).
One colony (colony A) of mice was pure breeding for short hair; a second colony (colony B) was
pure breeding for long brown hair.

a. A male from colony A was mated with a female in colony B.
i.
Give the genotype of the male from colony A and the genotype of female in
colony B. (2mks)
ii.
These two mice were crossed and produce a large number of offspring (F1).
Construct punnet squares to show this result (3mks)
iii.
Give the genotypes and phenotypes (ratio) of this F1 generation (2mks)
Genotypes:
Phenotypes:

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3 years 2021-07-25T11:49:04+00:00 1 Answers 4 views 0

A (i) a male from colony A HH and female from colony B bbhh

(ii) the offspring will be heterozygous for short brown hair

(iii) genotype 100%  Hhb, phenotype – 100% short brown hair

Explanation:

It is given that parent one is from Colony A that is pure breeding for short hair which means p1 is HH and parent 2 is from colony B that is pure breeding for long brown hair that means p2 is bbhh.

Cross between HH and bbhh

Gemetes : H, H, and bh, bh,

Punnet:

bh     bh

H    Hhb    Hhb

H    HhB    Hhb

Thus, the offspring will be heterozygous for short brown hair