From “Ancient humans were mixing it up” ( Eurekalert, September 2, 2011) we learn, “Anatomically modern humans interbred with more archaic hominin forms even before they migrated out of Africa, a UA-led team of researchers has found.”:
In a paper published in the Proceedings of the National Academy of Sciences, or PNAS, a team led by Michael Hammer, an associate professor and research scientist with the UA’s Arizona Research Labs, provides evidence that anatomically modern humans were not so unique that they remained separate.
“We found evidence for hybridization between modern humans and archaic forms in Africa. It looks like our lineage has always exchanged genes with their more morphologically diverged neighbors,” said Hammer, who also holds appointments in the UA’s department of ecology and evolutionary biology, the school of anthropology, the BIO5 Institute and the Arizona Cancer Center.
Note, however, that they did not discover this from DNA but from “a computational and statistical approach”:
“Instead, we looked at DNA from modern humans belonging to African populations and searched for unusual regions in the genome.”
Because nobody knows the DNA sequences of those now extinct archaic forms, Hammer’s team first had to figure out what features of modern DNA might represent fragments that were brought in from archaic forms.
Which means that the finding has the status of a rumour spread by a sharp-witted but sometimes unreliable neighbour.
“We think there were probably thousands of interbreeding events,” Hammer said. “It happened relatively extensively and regularly.”
Sure. These liaisons co-evolved with the rumour mill and Fault! Fault! Fault! divorce. Also, the earliest use of the term “tomcat” to refer to a human being …
“Anatomically modern humans were not so unique that they remained separate,” he added. “They have always exchanged genes with their more morphologically diverged neighbors. This is quite common in nature, and it turns out we’re not so unusual after all.”
Yes, but maybe the neighbours weren’t that unusual either.
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