In cats, the gene for black (B) and the gene for red (c) colors are associated with sex x chromosomes
In cats, the gene for black (B) and the gene for red (c) colors are associated with sex x chromosomes, but individuals heterozygous for this gene give a tricolor color. Black kittens were born from a tricolor cat, but among them were 1 ginger cat and a tricolor cat. Determine the phenotypes and genotypes of the father and kittens.
Let’s designate the chromosome containing the gene that causes the development of black hair in cats as XB, then the chromosome with the red hair gene as XB.
The tricolor color will be peculiar only to cats, they will be written like this – XBXв. The eggs they produce will look like this: XB and Xc.
Black kittens, according to the introduced designations, will be either XBXB, if they are females, or XBY, if they are males.
The male ginger kitten will be XвY.
The female tricolor kitten will be, like the mother cat XBXв.
In the described offspring, there are no red cats that would have the genotype XvXc, from which we can conclude that the father cat does not transmit the chromosome of the Xc species to the offspring. Consequently, his genotype will look like XBY, which externally will be expressed in a black coat.
