Check out this cool article on human evolution and genetic diversity!
Spoiler alert—it has this illuminating and affirming ending:
“Dr. Scerri speculated that living in a network of mingling populations across Africa might have allowed modern humans to survive while Neanderthals became extinct. In that arrangement, our ancestors could hold onto more genetic diversity, which in turn might have helped them endure shifts in the climate, or even evolve new adaptations.
“This diversity at the root of our species may have been ultimately the key to our success,” Dr. Scerri said.””
I find it silly that Neaderthals and Denisovans are classified as different species from modern humans. Given that they could cross freely with Homo sapiens, they were obviously different races of the same species.
I have heard that there’s far more human genetic diversity within Africa than in all of the world outside it, which is fascinating, as well. They have some very special and unique genes there. That’s wonderful.
The groups that moved out of Africa were generally extremely isolated and also closely related, so it makes sense that there woukd be less genetic diversity.
You know, I’ve wondered whether pale skin in cold climates was a genetic accident that wasn’t a disadvantage there, and therefore it persisted, or whether it was actually an advantageous adaptation there (less melanin = easier to get vitamin D from the sun during the few hours it was out, maybe?).
I’ve wondered this because it seems like we all ought to have dark skin – high melanin is such a strong genetic advantage because it protects so well against sunburn.
Yes but higher melanin also starts to slow down how much vit D you get/make from sunlight. If you’re near the equator and spending majority of your time outside then you’re fine. If you’re away from the equator and modern human spending lots of time inside and less and less time outside… you’re going to need vitamin supplements. And our highly processed foods tend to all have various vitamin supplementation.
Aha! That’s exactly what I’ve been wondering! Cool, so it would be a genetic advantage in low sunlight climates to have less melanin, then. Makes sense!
I wonder, is the same thing true of plants? Silver leaves are like a natural melanin for plants, protecting them from sunscald. They’re very good for desert climates with intense sun. I wonder if those would be less well adapted for northern climes?
