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Whether they were Homo neanderthalensis or Homo sapiens neanderthalensis is actually a matter of debate. It looks like the first generation human/neanderthal h

Whether they were Homo neanderthalensis or Homo sapiens neanderthalensis is actually a matter of debate. It looks like the first generation human/neanderthal hybrids were significantly less fertile than either alone given the sections of the neanderthal genome that have been systematically selected against, like all of the neanderthal mDNA. But still fertile enough to leave descendants, some of which were more fertile.

ljf 7y ago
It is interesting that we only seem to be descendants of pairing of male neanderthals and female homo sapiens - as there is no neanderthal mitochondrial in modern humans. Were there offspring from female neanderthals/human fathers? Did they survive, were they fertile? Or were there so few pairing that our lineage goes back to just a few individuals (similar to the compression in cheetah ancestors?) http://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals/interbreeding http://humanorigins.si.edu/evidence/genetics/ancient-dna-and... http://fire.biol.wwu.edu/hooper/204_06microevo.pdf http://fire.biol.wwu.edu/hooper/204_06microevo.pdf (I always have a real interested in neanderthal 'history', after finding that I have approx 4% neanderthal dna - more than 99% of people in the world).
- Symmetry 7y ago
  It's possible that only male neanderthal/female sapiens pairings produced offspring but that's probably not what happened. First generation descendants of a male sapiens and female neanderthal are going to have N mDNA and both complete N and S chromosomes so they'll have genes to code for proteins that'll form nice tight respiratory chains with the protiens from the mDNA. But in the third generation if you have another pairing with a sapiens you're likely to be missing N respiratory chain nuclear genes in half the offspring meaning half the fertilized eggs will have mitochondria that leak free radicals like seives and will go straight into apoptosis and never result in pregnencies. So in the third generation and onwards in a population that's mostly sapiens you're going to be having many more sons than daughters to mixed children and the mDNA will asymptotically die out. If it was a sapiens woman joining a neanderthal population it would be the sapiens mDNA that would die out. At least if I'm getting this right, I'm just a dilettante here. Plus generally neanderthals have bigger heads so I'd expect male sapiens / female neanderthals pairing to have less trouble with childbirth.

ljf 7y ago

It is interesting that we only seem to be descendants of pairing of male neanderthals and female homo sapiens - as there is no neanderthal mitochondrial in modern humans. Were there offspring from female neanderthals/human fathers? Did they survive, were they fertile? Or were there so few pairing that our lineage goes back to just a few individuals (similar to the compression in cheetah ancestors?) http://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals/interbreeding http://humanorigins.si.edu/evidence/genetics/ancient-dna-and... http://fire.biol.wwu.edu/hooper/204_06microevo.pdf http://fire.biol.wwu.edu/hooper/204_06microevo.pdf (I always have a real interested in neanderthal 'history', after finding that I have approx 4% neanderthal dna - more than 99% of people in the world).

Symmetry 7y ago
It's possible that only male neanderthal/female sapiens pairings produced offspring but that's probably not what happened. First generation descendants of a male sapiens and female neanderthal are going to have N mDNA and both complete N and S chromosomes so they'll have genes to code for proteins that'll form nice tight respiratory chains with the protiens from the mDNA. But in the third generation if you have another pairing with a sapiens you're likely to be missing N respiratory chain nuclear genes in half the offspring meaning half the fertilized eggs will have mitochondria that leak free radicals like seives and will go straight into apoptosis and never result in pregnencies. So in the third generation and onwards in a population that's mostly sapiens you're going to be having many more sons than daughters to mixed children and the mDNA will asymptotically die out. If it was a sapiens woman joining a neanderthal population it would be the sapiens mDNA that would die out. At least if I'm getting this right, I'm just a dilettante here. Plus generally neanderthals have bigger heads so I'd expect male sapiens / female neanderthals pairing to have less trouble with childbirth.