4 ms·
Wait, so placenta's existed before this virus gave us the ability for them to work? I would have guessed that the virus imparted the DNA at some earlier point,
by rocqua 6y ago
Wait, so placenta's existed before this virus gave us the ability for them to work?
I would have guessed that the virus imparted the DNA at some earlier point, and that DNA helped a placenta evolve.
- _Microft 6y agoThere seem to be a lot of different levels of maternal support for unborn offspring, ranging from „shelter“ by carrying eggs until they hatch to full life-support like mammals offer it. https://en.m.wikipedia.org/wiki/Viviparity https://en.m.wikipedia.org/wiki/Viviparity
- shellfishgene 6y agoMore specifically, the gene that enables syncytiotrophoblasts to do what they do enabled placentas to be compatible with an adaptive immune system. So the evoution of the placenta needs to be seen in the immune system context, a more simple immune system may not have a problem with a non-self embryo in the body. So the virus gene could be one of the factors that enabled a proto-placent to evolve along an adaptive immune system. [Note this is pure speculation, I haven't read up on the evolutionary timescales of either.]