This is where males and females choose as their mates those who have one unusual physical characteristic, not necessarily associated with "fitness" per se but simply something unusual. Perhaps the most plausible theory is that blonde hair and blue eyes arose because of a mechanism called sex selection. The trouble with this theory is that there is no evidence, from the scraps of Neanderthal DNA that have been recovered from bones, that there was any substantial interbreeding between them and Homo sapiens at all. Maybe the Neanderthals were blonde or red-haired and it is their genes which we have inherited.
#Black people with blue eyes skin#
Fair skin is better at making Vitamin D from the 8 per cent of the world's population have blue eyes weak sunlight found in northern latitudes.Īnother suggestion is that the strange skin, eye and hair colours seen in Europe are down to ancient interbreeding with the Neanderthals, who died out about 25,000 years ago. One theory is that Europe's cold weather and dark skies played a part. Why this should be remains unknown, and in particular how such mutations can have arisen so quickly since Europe was colonised by Africans just a few tens of thousands of years ago. Across the rest of the world people are almost uniformly darkhaired and dark-eyed. It is only in Europe that you will find large numbers of blondes and redheads, brunettes, pale skins and olive skins, blueeyed and green-eyed people living together in the same communities. Not only are Europeans far more likely to have blue eyes (95 per cent in some Scandinavian countries), they also have a far greater range of skin tones and hair colour than any other ethnic grouping. Those from Europe and the Near-East have many characteristics that set them apart from the rest of the human race. The finding that a rare mutation, probably dispersed in the rapid wave of colonisation that followed the end of the last ice age, highlights one of the great mysteries of human evolution: the oddness of Europeans. "Originally, we all had brown eyes," says Dr Hans Eiberg, who led the team.Īnd most people still do. The gene does not "make" blue in the iris rather, it turns off the mechanism which produces brown melanin pigment. The team, whose research is published in the journal Human Genetics, identified a single mutation in a gene called OCA2, which arose by chance somewhere around the northwest coasts of the Black Sea in one single individual, about 8,000 years ago.
Until now.Īccording to a team of researchers from Copenhagen University, a single mutation which arose as recently as 6-10,000 years ago was responsible for all the blue-eyed people alive on Earth today. Throughout history they have been the eyes that are prized.įrank Sinatra's were legendary, Paul Newman's melted a million hearts while Cameron Diaz's dazzle in modern Hollywood.īut how - and why - blue eyes arose has always been something of a genetic mystery. So, besides naturally occurring genetic blue eyes in dark skinned people, as previously discussed, understanding Waardenburg's is another avenue of accurately recognizing phenotype (gene expression) in eye color.Įveryone with blue eyes can be traced back 10,000 years to the Black Sea region Regarding the eye, color abnormalities come in three forms heterochromia (multiple colors), bilateral isohypochromia (pale blue eyes), or fundus (reflective) pigmentary alterations (spottiness). Waardenburg occurs once in every 42,000 births, and is a deficiency inherited from a single parent, who may or may not display similar characteristics. The boy in the picture is displaying two major symptoms of type 1, as does the previous boy (perhaps) () bright blue eyes and dystopia canthorum, a condition where the inner corners of the eyes are set more widely apart, but with normally distanced eyes. There are four types of Waardenburg Syndrome, with a mix of possible characteristics as the determinant.
Blue eyes as a Result of Wardenberg Syndrome
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