Comments on: Is the latest claim regarding “chimp-human” inbreeding a bunch of hooey?

By: Jim Thomerson

Jim Thomerson — Wed, 02 Sep 2009 14:09:52 +0000

Interesting news release about unique human genes.
http://www.sciencedaily.com/releases/2009/09/090901172832.htm

By: Jim Thomerson

Jim Thomerson — Wed, 02 Sep 2009 10:29:02 +0000

A paleontologist has said he was at a party where too much was imbibed. A female chimp was impregnated with human sperm. She appeared to become pregnant. In the sober light of day, the perps decided to dose her with hormones, and the pregnancy, if any, terminated. I was told this by a friend who was told it by the paleontologist. No reason to doubt the story.

By: Jared

Jared — Wed, 02 Sep 2009 02:36:26 +0000

Amplexus, I’m sure it’s been done before, it’s just a matter of finding out who did it and getting the data. Remember, not all scientific work gets published.

Also, it would be nice to have one of these in my garage…
http://www.helicosbio.com/Products/HelicostradeGeneticAnalysisSystem/HeliScopetradeSequencer/tabid/87/Default.aspx

By: Amplexus

Amplexus — Wed, 02 Sep 2009 01:53:43 +0000

Hey Greg, has anyone actually tried an experiment to see if say human sperm can signal chimp eggs to enter or whether they can go through some cell divisions?

I’d like to get some idea what the degree of zygotic barriers is. I mean is it total: as in no way it’s getting in. Or is it something like maybe 3 times out of a hundred it gets in.

Or maybe totally post-zygotic like it gets in but it just doesn’t develop.

I mean that would be the test. I sure it would cause a media firestorm if they found out but I remember I once heard it said “if you’re not doing a cross, it’s not genetics”

Haha, I have some dream that after I’m done with undergraduate and grad school that I could like find a suitcase of money and have a mad science lab and actually do these questionable experiments. LOL

By: Jim Thomerson

Jim Thomerson — Tue, 01 Sep 2009 21:56:26 +0000

I’ve seen the suggestion that a speciation process could be reticulated, rather than a clean divergence up two phyletic branches. I can well picture this happening. There is also introgression, the movement of genes from one species to another through hybridization events after speciation has occurred. If one reads early humans and chimps to mean both early humans and early chimps, then the statement is understandable to me, at least.

The how and why of sex chromosomes in interesting. I think they are rare in teleost fishes. There is a Cyprinodontid, Megupsilon aporus (monospecific genus) whose males have a very large Y chromosome. The same is true of a Rivulid, Gnatholebias hoigne;, but its sister species, G. zonatus, has a different number of chromosomes and no noticable Y. The two Gnatholebias species are morphologically very similar, but do not hybridize.

By: Greg Laden

Greg Laden — Tue, 01 Sep 2009 21:08:50 +0000

Must have. Some suggest that the chromosome number shift is very recent, ca a half million years ago.

By: sailor

sailor — Tue, 01 Sep 2009 20:49:33 +0000

I think we have one less chromosome than other primates. Was the mixing supposed to happen before we lost that?

By: Jared

Jared — Tue, 01 Sep 2009 20:14:26 +0000

Well, it wouldn’t “lead” to anything, modern chimpanzees can be traced back to that population and modern humans can trace back to another, but you’ve hit the nail on the head, these were two (maybe more) populations which were interbreeding; they weren’t very different, but the populations did diverge…

As for the definition of “species,” it really depends upon the context in which you’re using it…

By: James Hanley

James Hanley — Tue, 01 Sep 2009 20:13:41 +0000

the controversial claim that early humans and chimpanzees interbred before splitting into separate species.

This isn’t so much a statement “riddled with falsehoods” as a statement that is simply internally contradictory. You really don’t need any background in biology to recognize that, just a course in basic logic would allow a person to recognize that there can’t be “inter” action of any sort when there is only a single something. I hope that was just a careless statement that no editor caught, and not an accurate description of any claim that was ever made?

By: Alan Kellogg

Alan Kellogg — Tue, 01 Sep 2009 18:23:14 +0000

Wasn’t the original split between two different species of ape? One species would lead to the genera Australopithecine and Homo, while the other would lead to the genus Pan. So one can’t really talk about early chimp/early human interbreeding.