Recently, I have often come across articles and notes on the Internet on the topic "why there are no red female cats" and "why there are no tortie male cats". The whole argument boils down to the fact that these statements are an axiom.
I hasten to dispel the myths:
there are red female cats and tortoiseshell male cats.
But the latter are very rare, and, as a rule, they are infertile and have abnormalities in the development of the reproductive system (most often cryptorchidism). Although, of course, there are exceptions! I personally saw a fully mature tortoiseshell male cat not a cryptorchid.
But red female cats are far from being such isolated specimens, as they say everywhere!
Genetics is a complex science, especially since not all genes have been mapped onto chromosomes. But the red color seems to have been sorted out.
What do you need to understand basic?
1) in male cats, the sex chromosomes are represented by XY
2) the female cat has sex chromosomes XX
3) the Orange gene (red and cream colors) lies on the X chromosome
X°Y is a red male cat, its germ cells can carry either X° or Y in 1 cell
X°X° is a red female cat, its genitals are X°
X°Xb is a tortoiseshell female cat, its germ cells carry either X° or Xb in 1 cell
