Human-specific evolution in battling bugs and building babies

November 4, 2010, Public Library of Science

Although human and chimpanzee immune systems have many identical components, this is not the case for the family of killer cell immunoglobulin-like receptors (KIR) controlling white blood cells known as natural killer (NK) cells.

Published in the open-access journal on November 4, a paper by Stanford University researchers describes qualitative KIR differences, acquired after humans and separated 6 million years ago and mainly a consequence of innovation in the line. These differences open up an exciting avenue for explaining the differential susceptibility of humans and chimpanzees to devastating such as HIV/AIDS and malaria.

While immunological research has increasingly concentrated on the inbred laboratory mouse for the last half century, mice actually represent a poor model for human KIR because their NK cell receptors are so disparate from the simian primate counterparts. As a result, the researchers looked at chimpanzee KIR so that they could accurately compare them with the well-characterized human versions.

NK cells serve in both immune defense and reproduction; they contribute to early defense against infection and are implicated during the early phase of pregnancy, when uterine NK cells orchestrate enlargement of maternal arteries that will supply blood to the placenta and nourish the fetus. These vital NK cell functions seem subject to variable and competing selective pressures that have driven rapid KIR evolution and produced striking differences between humans and chimpanzees, as closely related as they are.

These distinctions derive from adaptations in the human line in response to selective pressures on human NK cells due to the competing needs of defense and reproduction. Whereas chimpanzees have a potent battery of KIR that appears aimed at fighting infection, the human KIR represent a functional compromise between battling bugs and building babies.

More information: Abi-Rached L, Moesta AK, Rajalingam R, Guethlein LA, Parham P (2010) Human-Specific Evolution and Adaptation Led to Major Qualitative Differences in the Variable Receptors of Human and Chimpanzee Natural Killer Cells. PLoS Genet 6(11): e1001192. doi:10.1371/journal.pgen.1001192

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kevinrtrs
1 / 5 (3) Nov 05, 2010
acquired after humans and chimpanzees separated 6 million years ago and mainly a consequence of innovation in the human line.

These distinctions derive from adaptations in the human line in response to selective pressures on human NK cells due to the competing needs of defense and reproduction

These vital NK cell functions seem subject to variable and competing selective pressures that have driven rapid KIR evolution and produced striking differences between humans and chimpanzees

Notice how these statements above can be eliminated from the article and make absolutely no difference whatsoever. These are simply wild speculations passed off as educated "fact". As I've now come to call them, guess-o-facts.The article is simply about the differences between the chimpanzee KIR and that of human beings. Nothing else. Those are the only facts that can be re-observed and substantiated. The wild speculations cannot be re-observed and hence cannot be confirmed.It's nonsense.
kevinrtrs
1 / 5 (3) Nov 05, 2010
For a different perspective on evolution[defined as molecules to man] and why it could not have happened, read this article here:
http://creation.c...mation-1
Skeptic_Heretic
5 / 5 (1) Nov 05, 2010
For a different perspective on evolution[defined as molecules to man] and why it could not have happened, read this article here:
http://creation.c...mation-1
You know, unless you'd like to actually come off as educated in conversations.

If you would actually like to know something about evolution, I'd strongly recommend you begin by studying basic chemistry and then biology.
Donutz
5 / 5 (2) Nov 05, 2010
As I've now come to call them, guess-o-facts.


As opposed to the source of your belief system, which I've come to call "superstition", or "belief in a magical sky fairy based on the collected works of stone-age shepherds".
You still haven't provided a single shred of evidence as to why we should prefer your brand of fairy tale over that of other organized superstitions. Or why we should accept any of them at all. Have you come up with any evidence for a deity yet? Didn't think so.
You can bleat on all you want about evolution, but until you've established at least the tiniest thimblefull of credibility, it's just trolling.

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