Why Women Are Stripey
Why Hacker News recommends it
Commenters point to it as the best short explanation of X inactivation and why calico cats and some human traits are mosaics.
What it is
Veritasium explains X-chromosome inactivation, where different cells in a woman's body switch off different X chromosomes, giving a mosaic pattern. It uses animation from the WEHI institute and connects to calico cat coloring.
Recommended by 2 HN commenters across 2 different months, 2015 to 2026.
What Hacker News said
Strong rec dacohenii · 2019-07 · on “Cat Colors”
This is only tangentially related, but Veritasium has a fantastic video that discusses the genetics behind the random color patterns of calico cats: [this video]
Recommends rndn · 2015-07 · on “How Can There Still Be a Sex Difference, Even When There Is No Sex Difference?”
The next article in this series on "Which sex is playing higher stakes reproductive game?" is also worth reading: [LINK] It reminds me of an interesting hypothesis I've read about the other day that the concept marriage plays a significant role in the success of our culture as it counteracts this difference. It allows more men to reach a social status at which they are motivated to be productive members of society. So we are possibly actively destroying a pillar of our culture as we are devaluing marriage. By the way, Veritasium has a great episode on why women are stripey: [this video]
Cites speeder · 2015-07 · on “How Can There Still Be a Sex Difference, Even When There Is No Sex Difference?”
This to me looks like the "very small number" refers to the ones where this is visible, not to the amount of them that has somewhere mosaic-style cell patterns. For example it is widely known now that if not most women, all women have mosaic patterns on their retina, this not only explains differences in disabilities (like the ocular albinism in the article, but also daltonism), but in perception: While men can see 3 primary colours, women can see 6, it is of course 2 kinds of each other, but still 6, this might explain why women treat colour differently than men (example: women are more interested in the colour of home decoration and clothes, they give more names to colours than men do, the
Cites somat · 2025-06 · on “Tetrachromatic Vision”
I assume it is the same reason that women have stripey skin. at ~ 100 cells, if the embryo has 2 X chromosomes the cell shuts one of them off, which one is random, those cells continue to multiply bringing their specific X chromosome with them. So women have genetically distinct blotches all over their body based on which cell disabled which X chromosome. I will have to leave this one for the scientists but I assume tetracromats got some of their cone cells from X and the rest from X` [this video] (veritasium: Why Women Are Stripey) The implication being, I don't think tetracromats have some sort of super vision, they just have what would be considered color blind if all their color cells were de
Cites dreamcompiler · 2026-04 · on “CRISPR takes a bold leap toward silencing Down syndrome's extra chromosome”
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. [this video]