You find a litter of stray cats in an abandoned car. The mother cat is tortoise

Question

You find a litter of stray cats in an abandoned car. The mother cat is tortoise shell fur (a mixture of black and tiger stripe) and she has seven kittens. Three females and four males. The four males are: 2 black, 1 tiger stripe and 1 white. The females are 1 black and 2 tortoise shell (like the mother). Explain the inheritance of cat fur colors. What color male did she mate with? Suggest a hypothesis for the white kitten.

This has been posted before but no one has explained the white cat in detail. Please explain as throughly as possible. I am not just seeking an answer but an explanantion. I have had three different answers as far as who the female cat mated with. Can someone provide a punnett square to explain the possiblity

Explanation / Answer

In cats, out of the various gene controllling factor is locted on the X chromosome. The genes have two alleles. for orange fur or tiger strip the gene code is XB and for black coat fur the gene coat is Xb. But it would be difficult to say that which gene will be dominat over the other. if we suppose that orange fur is dominant in this case then as per normal conditions animal inheriting one copy of each gene (genotype XBXb) should have orange fur. but surprisingly a female cat heterozygous at that locus will not be orange inspite of that it would be a mixture of black and orange fur which is known as tortoiseshell.

Expression of coat colour in males

In males the expression of coat colour is simple. Because only one allele exists for the gene in each cell, it will be expressed. And all males have only B or only b. There are no heterozygotes, because the Y does not carry the allele.

Expression of coat colour in females

In females the situation is some what complex because of a different phenomenon which prevents female from expressing expressing double the amount of X-linked gene products as the male, who has only one copy of each X-linked gene.

At the stage of embryonic development of female cat one of the two X chromosomes in each cellinactivates by supercoiling into a structure known as a Barr Body. This irreversible process is known as Lyonization; it leaves only ONE active X chromosome in each cell of the female embryo. Only the alleles on the active (uncoiled) X chromosome are expressed.

so now in this cat when a tortoiseshell cat has seven kittens out of which three are females and four are males, the male to which the female cat mated could possibly be a black or orange(tigerstrip) coloured or it could possicly mated with both of the males which were orange or black colour and their mating will result into four males are: 2 black, 1 tiger stripe and 1 white and females are 1 black and 2 tortoise shell.

But, what about white?
White is probably the most difficult to explain and understand. White is NOT a color.The gene that results in a white cat is one that allows a “cover” or “mask” of white to hide the true color of the cat. Many white cats are born with a spot of color on their heads, and that color will indicate the true color of the cat. Therefore, a cat that appears to be white will breed the same as any of the other colors shown above, depending upon which color it “masks”.

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