Results of Sex? It’s Complicated – And it’s a VERY long story


A happy Neanderthal

‘Got allergies? Blame your predecessors – your very distant predecessors.

Humans, as you know, were preceded in the evolution chain – the existence of whichsome continue to deny the existence of, despite the evidence – by several earlier life forms including one know as Neanderthals. That pre-human being expanded its presence as modern-day humans do: By mating with each other.

And like some – fortunately, relatively few – present-day humans, Neanderthals also sometimes mated with beings beyond their own ‘type’.  Just as the mating of a human with a different member of the primate order – a type of simian – infected humans with the virus leading to AIDS, Neanderthals who  mated with early humans passed on DNA causing present-day man to be allergic to the likes of cat dander, dust and pollen.

That,at least, is the suspicion described in an article published this month (March) in the journal Science. That report says that, more than is commonly believed – among people who’ve given this a second’s thought – Neanderthals and early humans (perhaps voluntarily) did things together that resulted in babies. (They might have been identified as Neandehumans, if speech were well enough developed then.)

As if that weren’t bad enough – like first sex in a bumper car wasn’t! – inherited DNA resulted in ‘the result’ having allergies that never would have cropped up in humans if . . . well, you get the picture. (Truth be told, humans might never have ‘cropped up’ either!)

The cited study has an attribution list nearly as long as the study itself — meaning, a lot of people worked on it, or double-checked its findings. And they collectively confirm early theories, Science says, that “our human ancestors interbred with other hominins after they left Africa more than 50,000 years ago . . . [and that] those sexual encounters may have played an important role in bestowing humans with biology that impacts our skin and hair, giving us infection-fighting advantages. Many of these genes are involved in immunity and likely helped our ancestors fight new pathogens that they were exposed to as they dispersed into new environments,” CNN later was told by University of Washington evolutionary geneticist Joshua Akey, who helped lead the study.

The research discovered that all who were analyzed, all of them non-Africans, had traces of Neanderthal, and different groups from Europe, Asia and Melanesia had distinctive blends of Neanderthal genes, which likely means humans repeatedly ran into these hominins, according to Benjamin Vernot, a postdoctoral student in genomic sciences at the University of Washington, who led the project.

“Studies like ours help to better understand the sources contributing to patterns of human genomic diversity,” Akey said.

While this study gives scientists new clues about the how that archaic DNA may have influenced various traits in modern humans, including their sensitivities that we describe as allergies, why those bits of DNA had that effect remain a mystery. Studies are, as you’d expect, ongoing.


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