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Originally Posted by Dr. Solar Wolff
Ok Vitor, you are having alot of fun with this but there is something here. The Rh-, Rh+ thing is a reproductive barrier. Reproductive barriers are only set up between species. What is the selective advantage of a woman who is only able to have one child? None, unless you know something I do not know. So if the Rh factor functions as a reproductive barrier and a mechanism of speciation, then what species are involved? It seems to me that the area where Rh- occurs in the highest frequency is also the area in which Neanderthal man survived the longest. Now, I am not saying you people with Rh- blood are any less human or in any way inferior to me or anybody else. In fact, I think we are all the result of sapiens-neandethal hybridization. What I am asking is: Isn't the Rh-, Rh+ dicotomy proof of Neanderthal survival?
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The way I always looked at it was that O- was the original blood-type of modern humans. The Rhesus factor and the different blood types A, B, AB were later mutations (in fact caused by additional molecules attached to the surface of blood cells) and they survived possibly because they confered some advantage to the populations in which they originally manifested themselves, ie. more resistance to certain diseases, etc.
The incompatibility between these blood types is merely a by-product of the way the immune system works. Just as the immune system recognises foreign pathogens by their strange surface configuration so the immune system of somene who lacks these molecules picks up on them as foreignand targets them for destruction causing an immuno-response.
In other words a Rh- mother's immune systems recognises Rh+ blood cells as foreign, as a blood group O subject recognises A or B blood as foreign, and it treats them like any other foreign cells and attacks them.