This gives me pause: it stated something as a fact, but did it have supporting data? or just state it as fact, with the assumption that everyone reading the article would accept it as fact?
No way for this blue random mutation could not have happened multiple times, in multiple populations? I find this hard to believe that all blue eyes trace back to a proverbial Adam (or Eve for the matter).
From an article in July 2018
Believing that blue eyes were likely the result of a genetic mutation, and thinking that the OCA2 gene determines the amount of melanin in our eyes, for some years researchers searched that gene for the mutation. But they couldn’t find it there.1
Then some researchers noted that two disorders that can result in albinism or reduced eye pigmentation, namely the Prader–Willi and Angelman syndromes, were caused by partial deletion not just of the OCA2 gene, but also another gene known as HERC2. Researchers subsequently discovered that the ‘blue eyes’ mutation is actually in the HERC2 gene, a gene that regulates the activity of OCA2.2 The mutated HERC2 gene strongly inhibits the OCA2 gene’s role in eye pigment production, drastically reducing the amount of melanin produced in the iris, resulting in blue eyes.
“Originally, we all had brown eyes,” explained lead researcher Professor Hans Eiberg of the University of Copenhagen, likening the HERC2 mutated gene’s effect on the OCA2 gene to that of “a ‘switch’, which literally ‘turned off’ the ability to produce brown eyes.”3 Given how little variation there is in blue eyes, the researchers conclude that all blue-eyed people have this same mutation, and share the same blue-eyed ancestor.
1 Williams, Z., and Orwig, J., All blue-eyed people have a single ancestor in common, businessinsider.com.au, 22 September 2017.
2 Eiberg, H., and 6 others, Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the
HERC2 gene inhibiting
OCA2 expression,
Human Genetics 123(2):177–187, 2008 | doi:10.1007/s00439-007-0460-x.
3 University of Copenhagen, Blue-eyed humans have a single, common ancestor, sciencedaily.com, 31 January 2008.
She must carry the recessive somewhere in there!
