The mutation tweaked one type of sugar molecule, Neu5Gc, produced by early hominids, the first great apes. About 2 million or 3 million years ago, just as human ancestors Homo ergaster and Homo erectus emerged in Africa, a genetic mutation halted the production of this molecule, and the prehuman immune system began to recognize it as a threat. As a result, researchers find, some hominids would no longer have been able to mate and produce offspring with other populations, potentially driving early humans apart from other apes."Over time, this incompatibility would reduce and the eliminate individuals with Neu5Gc," study researcher Pascal Gagneux of the University of California, San Diego, said in a statement.If the date is closer to three million years, it would have considerable implications for the emergence of Homo. There are many theories about where early Homo came from and what led to the transition from Australopithecus to what became the earliest members of our line. This will shed some light on these ideas and, hopefully, spur more research in this area.
Interestingly, this research is not as new as the story makes it out to be. There was a paper written by A. Varki in 2001 that dealt directly with this data. It can be found here. Varki, however, did not make the connexion with immune suppression response but focused, rather, on how the mutation affected brain evolution.
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