Sex-linked traits were first described by TH Morgan in fruit fly eyes 40-50 years after Mendel published his pea experiments. It was the first published finding that specifically linked a gene to a chromosome, providing considerable evidence for the chromosome theory of inheritance which was still hotly debated at the time.
He studied more than just pea plants I think, but I forgot what else.
Female cats are interesting because, iirc, which X-chromosome inactivation is done in regions rather than individual cells, so you get those grey + white regions, so each region only has one active gene so dominant vs recessive doesn't matter, but its different in the different regions. Not sure if some genes are autosomal that override it though? I feel like it must be given neither of the parents appear mosaic patterned and yet they have offspring with two different solid-colored offspring. Which also means we're seeing gene interactions, not just non-interacting autosomal genes as studied in pea plants (tall/short, wrinkly/smooth, green/yellow).
The X-inactivation originally happens in individual cells, but it happens during embryonic development and is maintained through cell division. The cells divide many, many times after that point, leading to the regions of shared inactivation you see in the black/orange patterning of tortoiseshell cats. There’s another gene (not X-linked) that can add white spotting to the mix, combined they make calico cats.
Five offspring not fitting in my punnet square! 🤨
Did Mendel study X-linked mosaic patterns in females?
Sex-linked traits were first described by TH Morgan in fruit fly eyes 40-50 years after Mendel published his pea experiments. It was the first published finding that specifically linked a gene to a chromosome, providing considerable evidence for the chromosome theory of inheritance which was still hotly debated at the time.
Pretty sure he studied pea plants. But, he first described the ideas of dominant and recessive genes.
He studied more than just pea plants I think, but I forgot what else.
Female cats are interesting because, iirc, which X-chromosome inactivation is done in regions rather than individual cells, so you get those grey + white regions, so each region only has one active gene so dominant vs recessive doesn't matter, but its different in the different regions. Not sure if some genes are autosomal that override it though? I feel like it must be given neither of the parents appear mosaic patterned and yet they have offspring with two different solid-colored offspring. Which also means we're seeing gene interactions, not just non-interacting autosomal genes as studied in pea plants (tall/short, wrinkly/smooth, green/yellow).
The X-inactivation originally happens in individual cells, but it happens during embryonic development and is maintained through cell division. The cells divide many, many times after that point, leading to the regions of shared inactivation you see in the black/orange patterning of tortoiseshell cats. There’s another gene (not X-linked) that can add white spotting to the mix, combined they make calico cats.
It's further complicated by the fact that one litter can have multiple fathers.
Wait, so mummy cat must also carry the recessive allele for the spockles, right?
It could be another allele that is recessive to both grey and spockles. More female offspring would probably tell us more on that.