Citat:
Ursprungligen postat av
HejaFinland
Nej de levde av jakt och fiske med mycket D-vitamin i kosten, som jägar-samlarfolken gjorde i Europa innan jordbruket. Jordbruk och lite solljus är de två drivande evolutionära faktorerna. Nordeuropa hade båda.
Bättre jämförelse är Kina och Korea där folk är ganska ljusa; de levde också relativt långt norrut och levde på D-vitamin-fattig kost (Jordbruk). Deras ljusa hud är orsakad av en helt annan gen än de gener som gör oss ljusa i Europa; så en helt separat evolution som gett samma resultat. "Konvergent evolution".
Alla nu levande blåögda har en gemensam stamfar:
"Everyone with blue eyes inherited a tiny genetic "switch" that dilutes brown pigment in the iris. This mutation, found in all blue-eyed people, emerged 6,000–10,000 years ago, meaning they all share one common ancestor."
"But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch," which literally "turned off" the ability to produce brown eyes." The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin. The "switch," which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris -- effectively "diluting" brown eyes to blue."
https://www.sciencedaily.com/releases/2008/01/080130170343.htm
Denne stamfar bör, om man följer de dna-spår som finns, ha levt i nordöstra Mesopotamien.
Mutationen tros dock ha uppstått tidigare, för 14.000 år sedan. Lite osäker vad man bygger det antagandet på.
Blåögdhet och ljus hud hänger ihop, även om man ibland ser att mörkare personer får blå ögon och ljusa personer bruna ögon.
"Most of us think of Europe as the ancestral home of white people. But a new study shows that pale skin, as well as other traits such as tallness and the ability to digest milk as adults, arrived in most of the continent relatively recently. The work, presented here last week at the 84th annual meeting of the American Association of Physical Anthropologists, offers dramatic evidence of recent evolution in Europe and shows that most modern Europeans don't look much like those of 8000 years ago."
https://www.science.org/content/article/how-europeans-evolved-white-skin#3adbe5f9-3f35-4808-90c6-33d5429ed53b