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Feminism: chat

I've just discovered the Y-chromosome bottleneck

77 replies

GarlicAnything · 27/08/2026 21:58

When reading that patriarchy's approximately 5,000 years old, I haven't found serious justifications for it. Arguments seemed mostly to be about men being buried with posher grave goods (but women have been buried with equally swanky goods after that) and a reduction in 'venus' icons (but we don't know what they were for, and goddess worship doesn't prove anything anyway).

It never occurred to me to look at DNA. Here it is, though it happened more like 7,000 years ago. Google says:

The Neolithic Y-chromosome bottleneck was a sharp drop in male genetic diversity that occurred globally between 7,000 and 5,000 years ago. 1, 2]

What Happened

  • Genetic collapse: Diversity in the male Y-chromosome dropped so fast that it looked like only one man reproduced for every 17 women.
  • Only men affected: Mitochondrial DNA (passed down through mothers) showed normal, steady growth. This rules out general disasters like famines, plagues, or climate change. 1, 2, ]

Why It Happened
Scientists link this event to the shift from hunter-gatherer groups to farming and agro-pastoralist cultures. Two main ideas explain the drop: 1, 2]

  • Patrilineal warfare: Early research suggests that wealth and power grew in male-dominated clans. Competing clans fought wars where entire family lines of men were killed, wiping out their specific Y-chromosomes. 1, 2, 3]
  • Peaceful social structures: Newer models show that strict patrilineal and patrilocal systems (where land and names stay with male kin groups) can naturally reduce Y-chromosome diversity over time through normal social fission and unequal reproductive success, without requiring massive violence. 1, 2, 3]

One man reproduced for every 17 women! No matter what narrative we superimpose on this, it's quite an unpleasant picture. 17 women getting pregnant for each impregnator. Men indisputably took control over women and dictated which men they could reproduce with.

I think the 'peaceful' patrilocal societies must've been established by force, since I can't imagine women all over the world cheerfully leaving their homes to join strangers' harems.

Y-chromosome diversity recovered in a rapid spate of 'star-shaped' explosions from 5,000 years ago, when cities and city-states became the norm. People from what had been discrete rural settlements moved to the cities and mingled, then the city-states started fighting each other and taking each other's populations as prisoners. This resulted in more men and genetic mixture, with the star shapes being patterns of Y diversity radiating out from the city centres.

Sadly, it doesn't look like the men gave up controlling women's reproductive options and living conditions, although far fewer of them had as many as 17 wombs at their disposal.

Women made a patchy comeback at times. Now archaeology's giving up its sexist assumptions and re-examining grave finds, it's becoming clear that many societies throughout history have been female-led and matrilocal. I'm happy to note that this seems especially the case in Britain - our Celts buried more 'warrior queens' than they did in mainland Europe, for instance, though of course there's still much more to be discovered.

Population bottleneck - Wikipedia

https://en.wikipedia.org/wiki/Population_bottleneck

OP posts:
GarlicAnything · 17/09/2026 03:19

GaIadriel · 16/09/2026 22:26

Sorry, bit of a ramble again. But I think people often try and analyse the world using social theory and in the process sometimes come to conclusions that don't necessarily reflect the clear observable reality (not referring to this discussion specifically, more in general).

I think if I met a big sexy viking who was happy to pay for me to be a lady of leisure I'd defo consider it. 🤣 As long as it wasn't in a controlling manner. Some men just like to be the provider and if they earn enough that their partner/wife doesnt need to work then they're often happy for them not to because they just want their loved ones to be happy.

OK, but your kept woman - no matter how benignly kept - has no more autonomy than a pet. If her keeper changes his mind, she's out in the cold.

It's hard to understand why you're bringing this up in a thread about world events where this was the norm:

  • They fought against Midian, as the Lord commanded Moses, and killed every man.
  • They burned all the towns as well as all their camps. They took all the plunder and spoils, including the people and animals.
  • Moses was angry with the officers. “Have you allowed the women to live?” he asked them.
  • "Now kill all the boys. And kill every woman who has slept with a man, but save for yourselves every girl who has never slept with a man."
  • The plunder remaining from the spoils that the soldiers took was 675,000 sheep, 72,000 cattle, 61,000 donkeys and 32,000 women who had never slept with a man.
(Numbers 31) Even you can't frame this as women choosing to go with the victors for an easy life!

... ... ... ...

This is thought to have happened about 3,400 years ago, by which time the Levant was already in the Late Bronze Age, more than a thousand years after the Y bottleneck released. Regardless of its accuracy, the story's a clear illustration of the accepted norms of Bronze Age warfare - kill all the men and boys, take the young women 'for yourselves'.

The scale would've been bigger by this point. Moses took a census of Israelites just before the raid on Midian: his tribe, the Levites, had 23,000 male descendants (Numbers 26). He didn't send any of them to battle as they were priests; his force was made up of men from the other tribes of Israel. All of them, however, received a share of spoils, including young women.

It's a masterclass in Y-chromosome propagation. To this day, half of all Jewish priests carry haplogroup J1. As we know, other male groups were achieving similar levels of domination elsewhere by much the same methods.

OP posts:
sawdustformypony · 17/09/2026 13:49

Thank you @GarlicAnything - I will read your post(s) with interest. However, I just wanted to comment on your paragrapgh back to me.

I don't think life expectancy was 15, by the way, at least once infancy was survived. It was probably more like 40 although there are lots of records of individuals living past 70.

I wasn't talking about life expectancy (which I agree with you - an average of 40 years sounds about right), but more the age when these neolithic humans would have their first born - so I was trying to guess the time it takes to pass one's Y chromosome on. I plucked the 15 years out of the top of my head. As usual wiki has something to say about this - and as usual it's a lot more complicated then at first glance. See

en.wikipedia.org/wiki/Generation_time

I had thought 15 years about right, (bearing in mind when we reach puberty weighted against a time a young woman in late neolithic times might be well fed and strong enough to give birth to a viable little chap (as we are utimately talking about the Y chromsome). So I was suprised to see the first figures in the research / review papers giving an average age of 23 years for women (and more like 29 for men (from memory - I read this the night before last)). Anyway the point is that (it seems) these ages are not - as I was guessing - when an indivdual woman's first gives birth, but instead it is the average of all her ages at she gives birth to all her children (or for men - fathering children) - so two completely different methods of calculation. One needs to go back to the original research papers in have any chance of understanding the data presented (and their methods of calculation - I'm not overly convinced at first glance - but hey, it's their field)

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