Originally posted by @sonhouseFrom memory, I think this is a matter of anatomy rather than genetics. The way bones form in conjunction with nerves and vessels does not lend itself well to faithful and reproducible regeneration of limbs. Other mammalian parts do regenerate: skin, blood, hair, muscle.
That would be a real boon for amputees if they can figure out how to introduce the genes responsible for regrowth. So at least lab specimens are still alive so future genetic research won't be lost as well.
Axolotl's are pretty cool (and incredibly rare) though. But we can't just introduce their genes and ... voila... new limbs.
Originally posted by @wildgrassI had a look at the Wikipedia page, the section on regeneration does not talk about why it does not work in mammals. However, it does mention that they heal without scarring, a property of human embryos, and that if injected with thyroid hormones to induce metamorphosis, their ability to regenerate is greatly reduced. So it seems to be to do with not fully leaving the larval stage. Humans do heal like this (although probably not to the extent of regrowing limbs) but only as embryos and we do not have a huge amount of choice about leaving that stage...
From memory, I think this is a matter of anatomy rather than genetics. The way bones form in conjunction with nerves and vessels does not lend itself well to faithful and reproducible regeneration of limbs. Other mammalian parts do regenerate: skin, blood, hair, muscle.
Axolotl's are pretty cool (and incredibly rare) though. But we can't just introduce their genes and ... voila... new limbs.
Originally posted by @deepthoughtIndeed, among tissues that do regenerate in mammals, e.g. skin and blood, there is evidence that developmental programs are being partially reactivated. The microenvironmental context is of course very different, however. The braking mechanisms in adult regeneration are very important (to avoid neoplasms).
I had a look at the Wikipedia page, the section on regeneration does not talk about why it does not work in mammals. However, it does mention that they heal without scarring, a property of human embryos, and that if injected with thyroid hormones to induce metamorphosis, their ability to regenerate is greatly reduced. So it seems to be to do with not ...[text shortened]... imbs) but only as embryos and we do not have a huge amount of choice about leaving that stage...