4. Cats have a gene that codes for the color of their fur. Suppose that a certain breed of cat can have black, gray, or white fu
r. Black fur is dominant, white fur is recessive, and gray fur is intermediate (i.e., cats with gray fur possess one allele for black fur and one for white fur). If a gray cat and a white cat have kittens, what phenotypes could the kittens exhibit •
A) black, gray, or white fur •
B) only gray fur •
C) black or white fur •
D) gray or white fur
A) black, gray, or white fur •
B) only gray fur •
C) black or white fur •
D) gray or white fur
2 answers:
Answer:
D) gray or white fur
Explanation:
Suppose the gene for fur color has alleles B and b. Here, B imparts black fur while b gives white fur. Since B is incompletely dominant over b, the heterozygous genotype "Bb" would give intermediate gray fur. Hence, the cross between gray (Bb) and white cat (bb) would give progeny in 1 gray: 1 white ratio.
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