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Comment by sheept | Hacker News Reader

> the X chromosome has a mechanism to shut itself down (which makes sense; otherwise cells in women would have twice as many gene products from the X chromosome as cells from men).

You can see this visually because not the same X chromosome is deactivated in all cells: it's what gives calico cats their color (almost all of them are female).

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Human women have stripey skin too, but you can't see it under normal light because unlike cats, skin tone in humans is not controlled by the X chromosome.

https://www.youtube.com/watch?v=BD6h-wDj7bw&t=225s

Can you link to a scientific article? I have severe doubts about that claim made on a random youtube video. In fact, I'd go as far as to claim that the content of the words here, are not correct. This is why I think a doi link to a research paper is necessary. I don't doubt that individual cells are, of course, chimeric, but I doubt the "stripey skin" claim. That one makes zero sense.

I just did a google search and this further confirms my suspicion. Thus I would like to ask for a link to a scientific article - until that happens I remain rather unconvinced.

https://link.springer.com/article/10.1007/BF00273442

I haven’t read it but I did find this

I agree about the need for verification, but Veritasium videos are usually well-researched and more accurate than "random" videos.

Here's one link:

https://www.sciencedirect.com/science/article/abs/pii/S07380...

That video seems to imply you can't see it under any light and the image there is pure visualization.

AFAIR this comes up visually when infected with certain diseases.

For a more practical example, how does this work for the daughter of a colorblind person (the colorblindness gene is on the X chromosome)? Do they have four types of cones?

Yes, but it's not limited to that case - there's two common variants of the green cone that respond to different wavelengths and people with two X chromosomes can have both, improving colour identification.

How does it feel to actually answer a question as a geneticist?...

> How does it feel to actually answer a question as a geneticist?...

Genetics is complicated.

If you really want to learn about this, all you need to do is search.

https://www.bbc.com/future/article/20140905-the-women-with-s...

I'm kind of late to this but for some context - bonzini knows me from a long time ago when I was still a genetics student and the joke here is that given where I am now in my career I still get to occasionally answer questions based on that background

> Human women have stripey skin too, but you can't see it under normal light because unlike cats, skin tone in humans is not controlled by the X chromosome.

Humans have 'stripey' skin because of somatic mutations, and it's not clear that there are X-chromsome-located skin color loci. Don't believe everything you see on Youtube.

Likewise humans with heterochromatic eyes are generally women.

> Likewise humans with heterochromatic eyes are generally women.

I haven't heard of this - where is this published? Here's a primer on eye color:

https://www.ncbi.nlm.nih.gov/books/NBK574499/

I was misremembering, it's actually cats where hetrochromatic eyes is associated with females. In humans there isn't any difference.

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