4 ms·

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

29 points by bikenaga 8mo ago

galleywest200 8mo ago
Ignorant question: would this mean older fathers are more likely to produce daughters?
- yorwba 8mo ago
  This study says yes, the effect becoming detectable at about 70 years of age: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2821811 https://jamanetwork.com/journals/jamanetworkopen/fullarticle...
- jleyank 8mo ago
  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.
bikenaga 8mo ago
Original title: "Men lose their Y chromosome as they age. Scientists thought it didn’t matter – but now we’re learning more"
rustyhancock 8mo ago
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.
mrguyorama 8mo ago
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.
- _aavaa_ 8mo ago
  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.
- gizmo686 8mo ago
  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.

29 points by bikenaga 8mo ago

galleywest200 8mo ago

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

yorwba 8mo ago
This study says yes, the effect becoming detectable at about 70 years of age: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2821811 https://jamanetwork.com/journals/jamanetworkopen/fullarticle...
jleyank 8mo ago
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.

bikenaga 8mo ago

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

rustyhancock 8mo ago

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.

mrguyorama 8mo ago

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.

_aavaa_ 8mo ago
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.
gizmo686 8mo ago
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.