Quite true. But it does speak to such matings as not being casual (ie, there probably haven’t been too many attempts). And you never know what wonders the laboratory might produce. For instance, the enzymes that the sperm uses to help penetrate the ovum might not be compatible betwee the two species, but that’s nothing that a nice little needle couldn’t overcome!
Still, if I had to bet, I’d bet on no viable hybrids (but I wouldn’t give that option heavy odds). Perhaps some ethically challenged scientist will be motivated to try a chimp/gorilla hybrid some time. A positive result would certainly up the odds for a viable chimp/human hybrid.
I’ve heard this before. I’m skeptical. I think this point would be extremely important in the evolution/creation debate. Can you please provide a reputable cite?
Is Scientific American reputable enough? Really, this is not very controversial, and any book on human evolution will likely point out that the data we have to date suggest gorillas split off the human/chimp/bonobo line about 7M years ago, then humans split off about 1-2M years later.
The wiki entry for ape does a very good job of describing the “evolution” of scientific thought about the phylogenetic relationship among the apes. Read the section entitled “History of hominoid taxonomy”.
Oen thing I am totally confused about is that the researcher say human and chimps (I really their ancestors) split and then came back together.
How do they know there wasn’t interbreeding for the millions of years they say they were not interbreeding? I know that the latest divergences being on the X chromosone points to interbreeding. But how do they know when and for how long they were seperate before coming back to interbreed and whent he interbreeding took place? How do they know they weren’t only partially seperated with interbreeding going on the whoel time before the final split?
Good questions, but I think beyond the scope of the sumamries I’ve read. I’m going to have to get my hands on the actual Nature article because I was thinking along those lines, too, as I was reading about this in the newspaper. The most I can get (and I’m not a geneticist, so I may be misunderstanding) is that they were able to measure the devergence time of a number of different genes. Presumably the divergence dates did not form a continuum, but showed two distinct peaks. How this technique is able to have that kind of resolution, I’m not sure.
After thinking about this I think it has something to do with the divergences on the X chromosome being later. Meaning that the populations had seperated to the point that only female hybrids could breed and pass along genes on the X chromosome and male hybrids would be sterile.
Please don’t take this as any more than my best guess.
I’m a little skeptical of this. Most baby birds and mammals seem to have more prominent foreheads than the adults, as well as less prominent snouts. It’s even been suggested that “infantile forehead bulge” helps to stimulate maternal or parental instincts among warm-blooded animals. Sorry, no cite, other than a Time Life Nature Series volume on animal behavior that I read years ago.
As for protochimps and protohumans breeding, why not? Horses and donkeys can interbreed and produce sterile mules and hinnies. At some time in the past, before those species had diverged as much, I’m sure the offspring would have been fertile as well.
I agree, but I think part of the confusion is the variety of ways this paper has been reported. The first article I read about it said the authors claimed that the human/chimp line first split 10M years ago, that the two lines diverged for 4M years, then merged again briefly about 6M years ago. 4M years isn’t out of the question, but it sure raised my eyebrows more than a little. Susequent articles have presented the findings differently, talking about a mixed population during that interval. That’s why I plan to get my hands on the actual Nature article and see for myself what these guys are saying. Unfortuantely, my little local library doesn’t subscribe to Nature, so I’ll have to make a trip to a bigger one sometime this week.
