Kosmos ~ Chapter 10

I think that the author’s point about cross-breeding resulting in a sterile offspring (horse + donkey = mule) is an intriguing point. However, I know that the reason for the mule being sterile is because the horse and donkey have a different number of chromosomes. So the real question then, is how many pairs of chromosomes did the Neanderthals have? Without preserved tissue, science nor technology cannot tell us for sure how many pairs of chromosomes Neanderthals had.

If in fact, however, humans and Neanderthals had the same number of chromosome pairs, then his assumption that the offspring of a homosapien and Neanderthal would be sterile holds no water. We know that modern humans and chimpanzees share somewhere on the order of 98% of their DNA makeup. However, the real question is how many chromosome pairs. All living modern apes (chimpanzees, gorillas, orangutans) all have 24 pairs of chromosomes while humans have just 23 pairs.

I *think* the branch for Neanderthals is much closer to present day, which would give Neanderthals a greater probability of having 23 pairs like modern man, which would largely debunk the authors argument about sterile offspring being the reason there is no evidence for cross-breeding.