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does anyone know if this or epigenetic inheritance only result from stress during the time the sperm were grown or whether sperm carry such information years af

does anyone know if this or epigenetic inheritance only result from stress during the time the sperm were grown or whether sperm carry such information years after stress, which has now gone - i.e. if one was stressed over some interval in the past but is now happy and relaxed, does one's sperm still carry the marks of stress from the previous stressfull period ?

klmr 8y ago
> this or epigenetic inheritance This is an instance of epigenetic inheritance. As for your question, we don’t know yet (also because these results are still terribly preliminary). It’s conceivable that stress permanently modifies something in the epididymis (where sperm is matured), and thus affects all sperm coming thereafter. It’s also possible, though probably less likely, that only currently present sperm is affected. From personal experience, working with sperm samples is a pain — the transcriptional signal you get is incredibly noisy, and every ground-breaking interpretation should be taken with a grain of salt.
- vbuwivbiu 8y ago
  ok now I'd like to know if these epigenetics marks are sensed by the egg and selected against - does the egg refuse to be fertilized by stressed sperm ?
  - klmr 8y ago
    The oocyte doesn’t have a direct way of recognising that sperm is stressed. However, stress does weird things to cells (the sperm, in this case), and the consequences of that are often severe. This definitely has an effect on the fitness of individual sperm cells, and purely stochastically this means that it’s more likely for healthy sperm to inseminate the egg. And after the fusion of sperm and egg, stressed sperm likely exhibits genetic damage (despite the topic on hand being non-genetic information), and this in turn makes it less likely that the zygote (fertilised egg) will be able to divide correctly. This leads to a spontaneous abortion of pregnancy — a process that naturally occurs more frequently than actually successful pregnancies (this happens within days of fertilisation and goes unnoticed). So to answer your question: the egg itself probably doesn’t have a way of sensing this directly but there are many factors that indirectly have a similar effect. Stressed sperm is selected against.
    - vbuwivbiu 8y ago
      superb answer thanks

klmr 8y ago

> this or epigenetic inheritance This is an instance of epigenetic inheritance. As for your question, we don’t know yet (also because these results are still terribly preliminary). It’s conceivable that stress permanently modifies something in the epididymis (where sperm is matured), and thus affects all sperm coming thereafter. It’s also possible, though probably less likely, that only currently present sperm is affected. From personal experience, working with sperm samples is a pain — the transcriptional signal you get is incredibly noisy, and every ground-breaking interpretation should be taken with a grain of salt.

vbuwivbiu 8y ago
ok now I'd like to know if these epigenetics marks are sensed by the egg and selected against - does the egg refuse to be fertilized by stressed sperm ?
- klmr 8y ago
  The oocyte doesn’t have a direct way of recognising that sperm is stressed. However, stress does weird things to cells (the sperm, in this case), and the consequences of that are often severe. This definitely has an effect on the fitness of individual sperm cells, and purely stochastically this means that it’s more likely for healthy sperm to inseminate the egg. And after the fusion of sperm and egg, stressed sperm likely exhibits genetic damage (despite the topic on hand being non-genetic information), and this in turn makes it less likely that the zygote (fertilised egg) will be able to divide correctly. This leads to a spontaneous abortion of pregnancy — a process that naturally occurs more frequently than actually successful pregnancies (this happens within days of fertilisation and goes unnoticed). So to answer your question: the egg itself probably doesn’t have a way of sensing this directly but there are many factors that indirectly have a similar effect. Stressed sperm is selected against.
  - vbuwivbiu 8y ago
    superb answer thanks