Men lose their Y chromosome as they age – how it may matter | Hacker News Reader

Men lose their Y chromosome as they age – how it may matter

theconversation.com

29 pointsbikenaga8 comments

Original title: "Men lose their Y chromosome as they age. Scientists thought it didn’t matter – but now we’re learning more"

Human species is "losing", ie evolving away from, the Y chromosome in general. Keeping up an entire Chromosome is expensive and "Inefficient" from evolution's point of view.

Human society meanwhile has disrupted a lot of "natural" processes of evolution, so I have no clue how this will play out.

Also, chromosome count is not as stable as you might intuitively think. There are hominidaes alive today with 48 chromosomes.

There are human men alive today without any Y chromosomes that present with standard male phenotypes without needing any medical intervention. Currently, the biggest symptom of this condition is infertility (which is often the point where most people learn they have it). However, on evilutionary timescales, it doesn't seem that far off for the remaining needed genes to migrate over as well. On a human timescale, it doesn't seem that far off for us to medically solve the infertility issue; although I imagine the ethics rules would prohibit such treatment if it leads to xx-male offspring.

Having said that, while chromosomal sex determination is not omnipresent, it does seem to be much more preserved than chromosome count.

Nothing’s been “disrupted”. Evolution is occurring the same way it’s always done: through random mutations in response to the environment and sexual selection.

Utterly bewildering that this can happen.

I'd never heard of it.

It does seem that it's in a sense pre cancerous although the article seems not to say so outright.

An acquired genetic change, following errors replication and mistakes in cell division that leads to cells having an "advantage". Associated with aging, smoking and increased mortality...

If you didn't know it was about this Y loss, it would seem to be directly referencing a pre cancerous condition.

Ignorant question: would this mean older fathers are more likely to produce daughters?

This study says yes, the effect becoming detectable at about 70 years of age: https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

It’s an anecdote, but in my experience older (40-ish) parents or those in places with chemical exposure seem to have a lot of daughters.

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