Thursday, 30 July 2009

We are all Africans

We Are All Africans
All non-African females are descendants of L3 line from Africa, and males have Y chromosome M-168

Nayan Chanda
Businessworld, 21 July 2009

Sweden’s well-known author Lasse Berg often begins his book talk with an attention-getter: “I am glad to see so many Africans in the room”. it invariably makes his (largely blond and Nordic) audience turn around to see where all the Africans are. Of course, Berg means everyone present. The author of Dawn over Kalahari: How Man Became Man proceeds to tell the story of how all humanity emerged out of the so-called dark continent and populated the earth.

The startling 1987 discovery of our common origin by Allan Wilson and Rebecca Cann by studying mtDNA (the maternal DNA) from samples dispersed all over the world led Newsweek to run a cover story with an image of an African Adam and Eve. In the ensuing years, massive amounts of genetic research has laid to rest any doubt about our African origin. While all non-African females are descendants of L3 line from Africa, our earliest common father was one with a Y chromosome marker, M-168.

The scientific evidence that we share the same African ancestry has been around for over two decades. Yet, in speaking about this to audiences across four continents, while presenting my book Bound Together I have encountered great surprise, and some scepticism.
Similarly, I read somewhere that about 25% of the European population could be descended from Julius Caesar. We really are all related.

This is not startling to me - it's something I have been aware of for ages - but I guess if you didn't believe in evolution or understand its implications, it might seem startling.


Yvonne Rathbone said...

I've known this for some time, too. And I'm often surprised at how much resistance I get from people of all races.

From what I understand, the findings of genome projects is that sub-Saharan African populations contain within their gene pool almost all human genes found on the planet. There are some few, very new, mutations that mostly have to do with obvious traits such as melanin production. The real difference between populations is in the subsets of the African gene pool found in other populations. Basically, whenever a subgroup leaves a parent population, it takes with it only a subset of the original gene pool, but almost never takes with it all instances of a particular gene. So the parent pool maintains the entire inventory while the migrating population carries a subset. There are differences between inventories of different migratory groups, but these groups do not readily match up to our modern notions of race. Race, as we commonly understand the term, is almost a completely socially constructed concept with much less correlation to actual genetics than most people are willing to believe.

This does not, of course, mean that race isn't "real," it's just not as scientifically based as we have been led to believe. (And now I will stop before I launch my Soapbox Rant #273: James Watson is an Idiot.)

Titus said...

How timely! Just posted this poem, passing it on if it's of interest.


for a heartbeat there is no heartbeat
between the hominid and me
she holds it steady hand like mine
I hold it steadfast in my gaze
and will not look away till I can bear the weight
for this is it this rock
the birth of homo habilis who bears me
these two million years past imagine
what happens in her mind that makes her reason
if I hit this with that then other will result
and I can use it glass-cased before me
is the Olduvai Core of Prehistory
and I can’t use language in order to grasp
this the moment of the start of our past

Olduvai Core: Africa: The Art of a Continent, Royal Academy, December 1995

Yewtree said...

Yvonne R: That's a new rant to me, so feel free to share :)

Titus: Wonderful poem, thank you. I like the enjambement. Nice to see you here.

Yvonne Rathbone said...

Oh, James Watson, who discovered the structure of DNA, has made a lot of stupid comments about the relative intelligence of blacks and whites, really irresponsible if not downright racist.

He starts off well; we really shouldn't assume that isolated populations of humans would evolve intelligence in the same way simply because we hold the ideal that all people are equal. But, there is no evidence that the meager amount of time current human populations have been isolated - to the extent they have actually been isolated - has resulted in important, or even measurable, changes to those genes that code intelligence. To imply otherwise is irresponsible. To phrase the debate in terms of "our" intelligence versus "their" (African) intelligence is a sign that for all his intelligence, James Watson is an Idiot.

Yewtree said...

I see what you mean - what a dork!

I think Howard Gardner's concept of multiple intelligences is useful; it includes natural intelligence, which is the ability to survive in the wild. Also, our environment has a huge part in what we develop skills in; if you're a University graduate, you might be very good at writing essays but rubbish at plumbing, or hunting, or lighting fires; but if you were plonked down in the middle of the wilderness, you'd probably die. Whereas someone who had excellent wilderness survival skills might not be able to write an essay, but they wouldn't get eaten by bears or die of exposure or hunger. But if you look at the normal distribution curve of intelligence in both societies, it's probably the same, but the skills are different.

Yvonne Rathbone said...

Yes, I find Gardner's idea of multiple intelligences to be very compelling. There's also the idea that craft work, like "shop class" and "home ec", and athletics require a lot more intelligence than is often assumed.

Also, just found this article in Science Daily from 2006 on human migrations:

Final paragraph:
"By the time you're done with this phase you can be 99 percent confident that there was recurrent genetic interchange between African and Eurasian populations," he said. "So the idea of pure, distinct races in humans does not exist. We humans don't have a tree relationship, rather a trellis. We're intertwined."

Ben017 said...

Note that evolutionary change accelerated with the development of agriculture and population expansion. A fair fraction are neurological and likely to affect behavior in some way. For example, you see new versions of SLC6A4, a serotonin transporter, in Europeans and Asians. There’s a new version of a gene (DAB1) that shapes the development of the layers of the cerebral cortex in east Asia.

"We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago," says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the National Academy of Sciences:

-- "We aren't the same as people even 1,000 or 2,000 years ago," he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. "The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence."

-- "Human races are evolving away from each other," Harpending says. "Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity." He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, "and there has not been much flow of genes between the regions since then."

"Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups."

The increase in human population from millions to billions in the last 10,000 years accelerated the rate of evolution because "we were in new environments to which we needed to adapt," Harpending adds. "And with a larger population, more mutations occurred."

Ben017 said...

***. "So the idea of pure, distinct races in humans does not exist. We humans don't have a tree relationship, rather a trellis. We're intertwined."***

Professor Steve Hsu notes that population genetics studies show that groups cluster. As genes occur in different frequencies you get average differences. His advice:

“it is important to note that group differences are statistical in nature and do not imply anything about particular individuals. Rather than rely on the scientifically unsupported claim that we are all equal, it would be better to emphasize that we all have inalienable human rights regardless of our abilities or genetic makeup.”