4 ms·

We have identical twins.

by dsr_ 7y ago

Jagat 7y ago
Most identical twins have very similar upbringings and share a lot of genetic code.
- dsr_ 7y ago
  By definition, identical twins share all of their genetic code.
  - maxerickson 7y ago
    Sort of. A single person's cells don't really all have identical DNA, because of mutations and so on. So it's one of those things that depends on how close you are looking.
  - akincisor 7y ago
    Not necessarily true: https://www.livescience.com/24694-identical-twins-not-identical.html https://www.livescience.com/24694-identical-twins-not-identi... paper (PDF) : https://www.researchgate.net/profile/Constantin_Polychronakos/publication/257756275_Somatic_point_mutations_occurring_early_in_development_A_monozygotic_twin_study/links/56cef7d708ae85c823430b5d.pdf https://www.researchgate.net/profile/Constantin_Polychronako...
  - dekhn 7y ago
    identical twins do not have identical genetic code.
- ajross 7y ago
  And many don't (share an upbringing, that is -- obviously they're genetically identical to at least the level that a clone would be). Twin studies are a foundational technique in studies of heritability. This is really well covered ground. I think the question stands: what is it about twin studies that is insufficient and needs to be replaced with ethically questionable techniques like cloning? For those who aren't aware: cloning of vertebrates isn't remotely mature technology. It remains routine for such an organism to be born with significant developmental flaws. Now tell me how you're going to get consent from such an individual pre-conception.
  - chr1 7y ago
    Of course we should not clone people with the unsafe technology, but we should work to improve it to the point where it is as safe as IVF. The problem with twin studies is that they are not repeatable, and the sample of just two is too small to make any strong conclusions. It's like saying we do not need particle accelerators, because there are high energy particles coming from space.
    - ajross 7y ago
      What about a clone is "repeatable" in a way that a twin study isn't? You aren't planning on controlling the upbringing of a real child, right?
      - chr1 7y ago
        You could have many children (10-100) living in well off families where malnourishment or lack of access to education would not be an issue. And I would gladly control upbringing of a real child, by raising it as my own, why do you think that controlling the upbringing is bad?
dota_fanatic 7y ago
Identical twins share a womb, and therefore even if you separate them at birth have already been subjected to identical "nurture" for ~9 months. Let's say you had four, all identical, split into two groups ran in parallel simulations. Two in the same womb then split at birth, the other two split at conception implanted in two separate mothers. Of the two borne to separate mothers, one mother is heavily stressed, chronically exposes the fetus to cortisol, while the other is very stable. When looking at outcomes between these pairs, how do you account for the difference in nature vs nurture when almost all of our twin studies rely on a shared womb, shared first 9 months of nurture?

We have identical twins.

by dsr_ 7y ago

We have identical twins.

Jagat 7y ago

Most identical twins have very similar upbringings and share a lot of genetic code.

dsr_ 7y ago
By definition, identical twins share all of their genetic code.
- maxerickson 7y ago
  Sort of. A single person's cells don't really all have identical DNA, because of mutations and so on. So it's one of those things that depends on how close you are looking.
- akincisor 7y ago
  Not necessarily true: https://www.livescience.com/24694-identical-twins-not-identical.html https://www.livescience.com/24694-identical-twins-not-identi... paper (PDF) : https://www.researchgate.net/profile/Constantin_Polychronakos/publication/257756275_Somatic_point_mutations_occurring_early_in_development_A_monozygotic_twin_study/links/56cef7d708ae85c823430b5d.pdf https://www.researchgate.net/profile/Constantin_Polychronako...
- dekhn 7y ago
  identical twins do not have identical genetic code.
ajross 7y ago
And many don't (share an upbringing, that is -- obviously they're genetically identical to at least the level that a clone would be). Twin studies are a foundational technique in studies of heritability. This is really well covered ground. I think the question stands: what is it about twin studies that is insufficient and needs to be replaced with ethically questionable techniques like cloning? For those who aren't aware: cloning of vertebrates isn't remotely mature technology. It remains routine for such an organism to be born with significant developmental flaws. Now tell me how you're going to get consent from such an individual pre-conception.
- chr1 7y ago
  Of course we should not clone people with the unsafe technology, but we should work to improve it to the point where it is as safe as IVF. The problem with twin studies is that they are not repeatable, and the sample of just two is too small to make any strong conclusions. It's like saying we do not need particle accelerators, because there are high energy particles coming from space.
  - ajross 7y ago
    What about a clone is "repeatable" in a way that a twin study isn't? You aren't planning on controlling the upbringing of a real child, right?
    - chr1 7y ago
      You could have many children (10-100) living in well off families where malnourishment or lack of access to education would not be an issue. And I would gladly control upbringing of a real child, by raising it as my own, why do you think that controlling the upbringing is bad?

dota_fanatic 7y ago

Identical twins share a womb, and therefore even if you separate them at birth have already been subjected to identical "nurture" for ~9 months. Let's say you had four, all identical, split into two groups ran in parallel simulations. Two in the same womb then split at birth, the other two split at conception implanted in two separate mothers. Of the two borne to separate mothers, one mother is heavily stressed, chronically exposes the fetus to cortisol, while the other is very stable. When looking at outcomes between these pairs, how do you account for the difference in nature vs nurture when almost all of our twin studies rely on a shared womb, shared first 9 months of nurture?