Question

Calico cats have two genes that govern their coat color. One gene codes for the white undercoat and the other codes for the fur colors black and orange and this gene is X-linked. We will look at the gene for black and orange fur color only. In this situation, both black and orange are codominant, so that heterozygous individuals are a different phenotype.

Based on this information, what would black, orange and calico female cats' genotypes be?

What would be the genotypes for males of the same colors?

What would the male and female offspring of a male black cat and a female calico cat look like?

Is it possible for a male cat to have the calico coat pattern? Explain.

Answer 1

1. the genotype of female calico cat will be XBXb

orange fur colour is dominant whereas black fur colour is recessive

since these genes are X-linked and females have two X genes, orange black calico cats are heterozygous

2. In case of male cats there are two possible fur colours, because males have only one X-gene

• orange male cats carry the dominant allele
• black cats carry the recessive allele

there's another possibility of orange black calico male cats. It occurs if it is a klinefelter male i.e. the male cat inherits two X chromosomes (one with a dominant allele and the other with a recessive allele besides a Y-chromosome)

the klinefelter male cat genotype is XBXbY

3. if a male black cat with a genotype XbY and a female calico cat with a genotype XBXb are crossed,then the possible gemetes formed are

• Xb
• Y
• XB
• Xb

the resulted progeny consists of two female and two males

• orange black female calico cat XBXb
• orange male cat XBY
• black female cat XbXb
• black male cat XbY

4. Yes, it is possible for a male cat to have calico cat pattern if it is a klinefelter male as dicussed above in 2nd subquestion