Hi Murph! I was wondering something…
In your video talking about tortoiseshell cats and using something that isn’t a punnet square, you talked about the male kitten only taking the colour from the mother and nothing from the father.
Is this true for every male kitten, or only males with a tortoiseshell mother?
Sorry if you said this somewhere and I missed it.
Females have 2 X chromosomes, males only have 1.
Draw a punnett square for a female with 2 Xs mating with a male with only 1 X:
As we can see, there's a 50% chance of a male offspring and a 50% chance of a female offspring
but remember: chromosomes are made up of genes! those genes do things!
One of the genes that the X chromosome has in cats is the O locus, and what it does is determine if a cat is ginger (O allele) or non-ginger (o allele).
Now, let's do this same punnett square again, but zooming in on that O locus:
This is a ginger mom and a non-ginger father. As you can see, female offspring get 2 Xs and thus receive ginger-locus info from both parents. However, male offspring only receive an X from mother, meaning they only get ginger info from mother.
THIS is what we mean when we say "color comes from mom" or anything similar: male offspring only receive 1 X from mom, and thus male offspring will only receive X-linked genetic info from mom