Thursday, September 02, 2004

Shades of Humanity

A friend sent me the piece below -- it's not news, but it's worth passing around anyway. I saw a programme on the National Geographic sometime last year (I think) following the gene-trail that leads from the San of the Kalahari Desert right across the globe, touching every one of us, from Australian aboriginal to blue-eyed Swede. It was impressive but also rather saddening to think that the very people who may represent the 'parent' community of modern humans is so tragically reduced in numbers, so compromised in its ability to survive intact on its own terms. Anyone who saw the movie "The Gods Must Be Crazy" will remember the poignant representation of the Kalahari Bushmen -- it's great to think we are related! -- but it's also very sad to see, in more recent documentary films, how very limited their degrees of freedom are.

The following article came to me without identification. If anyone knows the source or can find out, I'd be glad to include that information.

UPDATE: Thanks to the tirelessly efficient ZIGZACKLY (website listed to the right) I can now post the name and correct title of this piece. I am hoping it is in the public domain -- and if not, Zig has helpfully posted the original location of the piece and the source of more articles by the same author in his comment below.

A PALER SHADE OF BLACK
by LINDA BECKERMAN.

There is no such thing as race, thanks to the genetics revolution. The Human Genome Project (HGP) has determined unequivocally thatthere is the same amount of genetic variation among individualswithin a so called racial group as there is between individuals in different racial groups. What that means is that there is no real genetic difference between blacks and whites or between whites and Asians or between any of the so called races.Wonder why it's been so hush-hush? I mean, you would think this would be big news. Certainly on the order of Galileo stating that the Earth goes around the Sun and not vice versa. But you haven't heard it on NBC or read it in your local newspaper. It's more or less kept within the high brow community as if the common every day man in the street just couldn't take it.

So you can read about it in the Atlantic Monthly or New York Times, but not your home town newspaper. And some professors on ivory tower college campuses are scrambling to prove itisn't so, just like there some who argue that Darwin was a fruitcake and evolution a stunt he pulled to grab the limelight.But if we are all one race, which race are we? One answer is the cute one that we are the "human race". But buckle your seat belts folks, because the genetic answer is that we are all really black. And white people are pale adaptations of black people that evolved during the past 140,000 years.From whence does this white skin come? Weren't we all taught that it was the black people who evolved black skin and it happened so they would be protected from getting skin cancer?Forget it. Scientists have thrown the whole notion out. Here's how evolution works. If you don't live long enough to reproduce, your genes are lost to the gene pool forever.

There being no high school back when Humans came into being, females started reproducing around the age of 13. Skin cancer develops later in life when the female has already reproduced and her genes have entered the world gene pool. Bye, bye skin cancer theory.What scientists now believe is that everyone started out with dark skin in the first place because it is protective against absorbing too much Vitamin D, which is toxic. Too much vitamin D causes calcium to be pulled from the intestines and bones and deposited in soft tissues all over the body, damaging the kidneys, heart and blood vessels. Dark skin screens out UV radiation and your body, which uses UV to produce Vitamin D, produces less of it - a real evolutionary advantage at the lower latitudes where we began.So where did the 10,000+ shades of paler brown, beige, pink, white and what Crayola crayons used to call "flesh" come from?

Archaeological data places the origin of genetically modern humans in sub-Saharan Africa approximately 140,000 years ago. Humans then began migrating out of Africa in successive waves, starting approximately 100,000 years or 5000 generations ago. Now that scientists have mapped the human genome, they are homing in on when each wave began their outward bound journey and where they migrated to. So far they have confirmed that everyone on the entire planet, even the 1.3 billion Chinese, have a common ancestor back in Africa.For example, the first wave appears to have been a migration to the Middle East and then eastward and northward from there. Somegeneticists studying the human genome map believe that in a later north moving wave, which occurred about 60,000 years ago, a mere 50 people inbred together across successive generations to create all the people who now occupy Europe (excluding recent immigrants, of course).

But wait a minute, I have blond hair, blue eyes and my hair isn't nappy and I don't have thick lips. So how can my great, great, etc grandpappy be a black African? It's all from lines of genetic inheritance splitting apart and then coming together again. Lines of genetic inheritance, or lineages, split apart when there is a mutation that is evolutionarily advantageous, meaning the mutation makes it more likely for someone to reproduce greater numbers of offspring that survive. Someone with a non advantageous mutation has offspring that are less likely to survive.So as humans migrated out of Africa, why did dark skinned peoplestart losing the genetics Powerball Lottery to their paler kin?

Lower UV levels in the sunlight of the more northern latitudes meant a dark skinned individual's body could not produce enough Vitamin D. Insufficient Vitamin D would then result in a child developing rickets. A child with rickets would not likely reproduce either because it would die before it could or because its pelvis would be so deformed it could not pass a child through the birth canal. Its genes would be lost forever. So lighter skin, and more absorption of Vitamin D at higher latitudes would be an adaptive genetic advantage. Interestingly, in high latitudes where some people still retain dark skin, such as with the Inuit in the Arctic, the people obtain significant amounts of Vitamin D from eating fish and sea mammal blubber.

Seal blubber aside, what about all the other features that make us look so different? Mutations that endure are often advantageous to specific climates. For example, the tall thin body of the Masai warrior dissipates heat while the short squat body of the Inuit retains it. Long northern European noses moisten and warm the air before it reaches lungs, while in Africa short noses remain because the air is already moist and warm. The Asian's eyelid folds protect their eyes against dry sandy desert winds and wind driven snow. In the far north, light sensitive blue eyes allow people to see better when it is dark much of the year. The tightly coiled hair of the African keeps the hair off his neck so he remains cooler.

All these diverse physical features promote the promulgation of different linesof inheritance, or ethnic lineages.Countering this splitting apart of ethnic lineages is the melding through interbreeding between different ethnic lineages. If you walk the Silk Road from Persia to China, across the southern flank of Asia, you will see a continuum of physical feature change. You will not be able to tell where the European look ends and the Asian begins. Remember all those shots during our assault on the Taliban in Afghanistan and the TV scans of Afghani children? How many looked European and how many looked Asian?Many mechanisms for melding ethnic lineages have been at play. The rape part of the plunder and pillage drill by invaders, traders passing through with silver to buy bedtime favors, marriages for political convenience to form alliances between not so friendly tribes, and the boy and girl from neighboring tribes sneaking out for a little tryst under the stars, have all contributed to the recombining of diverse ethnic lineages.

So what we have instead of the meaningless terms Caucasian, Negro, Asian, etc, is a large multiplicity of ethnic lineages, all of whom descended from a only a single black race. So don't forget, next time you fill in the U.S. Census you should write in the word Black next to the question about your race, regardless of your shade of pale.

4 comments:

Amrobilia said...

Oooh! This is all so familiar! It could be from Matt Riddley's "Genome" or "Guns, Germs and Steel" by Jar(r)ed Diamond...but I'm not very sure.

zigzackly said...

The Goog tells me the piece is called A Paler Shade of Black, and it's by Linda Beckerman. You can see the essay at http://www.geocities.com/beckermanlin/palerblack.html and her other essays at http://www.calresco.org/beckermn/index.htm

Marginalien said...

Hi Zig and thanx again, as always for your prompt and fruitful research. I'll update the info in the post.

Amrobilia, yes, it IS reminiscent of both books, but it cuts to the chase rather neatly and succinctly, I thought.

Amrobilia said...

There you are!