5 ms·

The human body is incredibly good at detecting unviable mutations during pregnancy and it results in a miscarriage or other failures early on. This would be a

The human body is incredibly good at detecting unviable mutations during pregnancy and it results in a miscarriage or other failures early on. This would be a much better indicator to look at than whether the children who survived pregnancy had excess mutations.

CryptoPunk 6y ago
While that is also a very important indicator, what proportion of viable pregnancies produce children with mutations I would argue is an even more important metric to study.
- whoomp12342 6y ago
  it is an important metric if it has substance, but according to the above it has very little variance. Knowing how many pregnancies failed versus how many failed prior to the event could give us a better indicator of the damage caused.
  - sitkack 6y ago
    I think the question I feel the hive mind wants to answer is, "How much radiation can the species live with and not go extinct". If the birth rates are lower and mortality right is higher we can 'make up' for that. But if the offspring accrue hereditary damage, any amount is too much. We will have many many tough decisions to make due to the climate crisis.
    - Symmetry 6y ago
      And it's not just a matter of how much radiation either. Zap a bunch of fruit flies with a dose of x-rays all at once and see the next generation come out horribly mutated. Give them that same dose of radiation over the course of a month and see a perfectly healthy next generation.
      - ipaddr 6y ago
        Has that happened flies or animals that are immune to high radiation? I could see the next generation having horrible mutations, I could see the genes correcting some of this in the 3rd generation. I could see some of mutations living on but resistance to radiation would be so extremely useful we would build materials out of them which we are not doing today.
  - betterunix2 6y ago
    That was my first thought when I saw the title. IIRC roughly 1/3 of pregnancies end within weeks, often before a woman is aware that she is pregnant, almost always because of a genetic mutation. Given that, if the miscarriage rate is higher, that would indicate that there is indeed an impact, but that our genome is very good at preventing dangerous mutations from propagating. Another possibility is that error-correcting mechanisms are good enough to deal with whatever impact exposure to that level of radiation had. One hypothesis about meiosis and genetic recombination is that it serves as an error correcting process, where damaged genes on one chromosome can be repaired using corresponding genes from the other chromosome.
Symmetry 6y ago
That's very true but even if these forces catch 99% of significant mutations then you'd still see an increase in pregnancies resulting from that remaining significant mutations over baseline. But more importantly, our genomes have a lot of "junk DNA" where a mutation will not affect anything at all and almost everyone has these. From the article it looks like these were the mutations the researchers were looking at.
- refurb 6y ago
  “Junk DNA” as a concept is pretty dated. It used to refer to non-protein encoding regions of DNA. In our infinite wisdom we assumed these segments of DNA had no purposes yet it turns out they play an important role in DNA packing and unpacking which directly influences gene expression.
- BitwiseFool 6y ago
  I remember hearing a hypothesis that "junk DNA" acts as a kind of shielding against mutations. From a probability standpoint, the more non-coding DNA you have, the less likely an error is to hurt the lifeform. Taken to an extreme, if every DNA sequence did something a singe error would cripple the organism.
  - syrgian 6y ago
    However, the probability of the DNA getting hit would increase linearly with the amount of junk DNA, wouldn't it? So the chance of good DNA getting hit is exactly the same as without junk. Not sure how it would help shielding the good DNA, unless it acted as a barrier.
    - selectodude 6y ago
      Mutations from radiation come from particles literally slamming into the DNA and screwing it up. The more spaced out the important parts are, the lower the probability that the particle hits a piece of DNA that’s important.
      - 6y ago
giantg2 6y ago
Aren't some of these early miscarriages not even known by the woman? Wouldn't that make it difficult to measure?
lampe3 6y ago
I was born in August 1986. In northern Poland. I was born in the 26 pregnancy week. 40 is the avg. Even if it was not near Chernobyl there were more miscarriage then usual. So yes looking at the children that survived is not the correct way looking at it. I also know that getting legit data for that is nearly impossible.

CryptoPunk 6y ago

While that is also a very important indicator, what proportion of viable pregnancies produce children with mutations I would argue is an even more important metric to study.

whoomp12342 6y ago
it is an important metric if it has substance, but according to the above it has very little variance. Knowing how many pregnancies failed versus how many failed prior to the event could give us a better indicator of the damage caused.
- sitkack 6y ago
  I think the question I feel the hive mind wants to answer is, "How much radiation can the species live with and not go extinct". If the birth rates are lower and mortality right is higher we can 'make up' for that. But if the offspring accrue hereditary damage, any amount is too much. We will have many many tough decisions to make due to the climate crisis.
  - Symmetry 6y ago
    And it's not just a matter of how much radiation either. Zap a bunch of fruit flies with a dose of x-rays all at once and see the next generation come out horribly mutated. Give them that same dose of radiation over the course of a month and see a perfectly healthy next generation.
    - ipaddr 6y ago
      Has that happened flies or animals that are immune to high radiation? I could see the next generation having horrible mutations, I could see the genes correcting some of this in the 3rd generation. I could see some of mutations living on but resistance to radiation would be so extremely useful we would build materials out of them which we are not doing today.
- betterunix2 6y ago
  That was my first thought when I saw the title. IIRC roughly 1/3 of pregnancies end within weeks, often before a woman is aware that she is pregnant, almost always because of a genetic mutation. Given that, if the miscarriage rate is higher, that would indicate that there is indeed an impact, but that our genome is very good at preventing dangerous mutations from propagating. Another possibility is that error-correcting mechanisms are good enough to deal with whatever impact exposure to that level of radiation had. One hypothesis about meiosis and genetic recombination is that it serves as an error correcting process, where damaged genes on one chromosome can be repaired using corresponding genes from the other chromosome.

Symmetry 6y ago

That's very true but even if these forces catch 99% of significant mutations then you'd still see an increase in pregnancies resulting from that remaining significant mutations over baseline. But more importantly, our genomes have a lot of "junk DNA" where a mutation will not affect anything at all and almost everyone has these. From the article it looks like these were the mutations the researchers were looking at.

refurb 6y ago
“Junk DNA” as a concept is pretty dated. It used to refer to non-protein encoding regions of DNA. In our infinite wisdom we assumed these segments of DNA had no purposes yet it turns out they play an important role in DNA packing and unpacking which directly influences gene expression.
BitwiseFool 6y ago
I remember hearing a hypothesis that "junk DNA" acts as a kind of shielding against mutations. From a probability standpoint, the more non-coding DNA you have, the less likely an error is to hurt the lifeform. Taken to an extreme, if every DNA sequence did something a singe error would cripple the organism.
- syrgian 6y ago
  However, the probability of the DNA getting hit would increase linearly with the amount of junk DNA, wouldn't it? So the chance of good DNA getting hit is exactly the same as without junk. Not sure how it would help shielding the good DNA, unless it acted as a barrier.
  - selectodude 6y ago
    Mutations from radiation come from particles literally slamming into the DNA and screwing it up. The more spaced out the important parts are, the lower the probability that the particle hits a piece of DNA that’s important.
    - 6y ago

giantg2 6y ago

Aren't some of these early miscarriages not even known by the woman? Wouldn't that make it difficult to measure?

lampe3 6y ago

I was born in August 1986. In northern Poland. I was born in the 26 pregnancy week. 40 is the avg. Even if it was not near Chernobyl there were more miscarriage then usual. So yes looking at the children that survived is not the correct way looking at it. I also know that getting legit data for that is nearly impossible.