A Distinguished Race

Part One. Presented by Evolutionary Biologist Steve Jones
BBC World Service, Programe: Discovery
Aired 11/4/2010 (audio fail no longer availiable)

“if we were to talke a walk , a long walk from England over the channel, though europe into western asia, into eastern asia, and then were to double back on ourselves and to travel though the mediteraninan region into africa. What we would see are gradual changes from one human population to another. So yes, we see diffeneces from one extreme to another but those diffences grade gradually from one another, differences in skin pigmentation and other physical features. And so this clearly indicates that this veriation is like a gradient, its clinal in its distribution and there are very few if any abrupt discontinueties that would allow us to erect any distinct ratial or other named categories.”

Nina Cheblonski, Pincelvania University

“We shade into eachother, its there more or less black and white.”

Melononin is what what is mostly responsible for our colour and there is some eveidence that there has been three populations which have lost this independantly of eachother thoughout our long history.

1. well over 100 000 year ago – an extinct race of humanity

2. western uropeans

3. eastern asians

Why did we go light coloured? – to capture precious uvb to produce Vitamin D  and make us reproductively productive.

Not getting enough Vitamin D has similar affects to rickets in children, bowing of legs and deformation of pelvis. In adults it means softening of bones and longterm depression of immune system and can include hightend suseptability to some cancers.

“Western Europeans clearly had this mutation but equally lightly pigmented eastern asians did not. the conclussion then was: people in aisia had lost pigment independantly, so this has now happned twice then in modern population.”

When talking about eyes, they split into only two groups: blue eye colour and non-blue eye colour. ie. all non-blue eye colours, apart from appearance are the same.

Eyes that appear blue in colour, let in more light than brown or hazel. The idea is, that living up north with long and extremeley dark winter months, populations evolved, one hypothesis is that the amount of sunlight that is able to enter the eye has an influence on the likleyhood of depression, wich seems to have an amazing impact on the natural selection that occured in order to create eyes with this quality, wich appear to us as blue in colour.