X Inactivation

The podcast discusses X inactivation, also known as lyonization, named after Mary Lyon. It explains why calico and tortoiseshell cats are mostly female due to X inactivation, where one X chromosome in females becomes inactive, forming a Barr body. The process is described from the zygote stage, highlighting the randomness of which X chromosome is inactivated. The genetic basis of cat coloration, including epistasis, is explored. The podcast also touches on rare occurrences of X inactivation in humans, such as Klinefelter syndrome and disorders affecting sweat glands.

Describe the process that leads to one X chromosome becoming inactive in female cells.

What is epistasis and how does it relate to the coloration of calico cats?

Can male cats be calico, and if so, under what circumstances?