New Twist On Out-Of-Africa Theory

ABC Science News ^ | 7-14-2004 | Judy Skatssoon

[blam]

New twist on out-of-Africa theory

Judy Skatssoon
ABC Science Online
Wednesday, 14 July 2004

Homo erectus, the species thought to be the first to leave Africa for Eurasia in the out-of-Africa model of human origin (Image: Science)

Early humans made love, not war, according to new DNA analysis presented at a genetics conference that gives a new twist on the out-of-Africa hypothesis of human origins.

U.S. researcher Professor Alan Templeton of Washington University, St Louis, debunks the prevailing version of the out-of-Africa hypothesis, which says early humans migrated from Africa and wiped out Eurasian populations.

Instead, they bred, he told the Genetics Society of Australia's annual conference in Melbourne this week.

Templeton said his evidence didn't support the so-called replacement theory in which African hominids caused the extinction of other Homo species.

Instead, he said his analysis of the human genome showed prehistoric gene-swapping created a single evolutionary lineage beginning in Africa and ending where we are today.

He looked at mitochondrial DNA, as well as DNA on a range of chromosomes including X and Y.

"The genetic legacy of current humans is predominantly of African origin," he said.

Templeton is the first to suggest expansion out of Africa occurred in three waves: 2 million years ago, 800,000 years ago and 100,000 years ago.

The alternative view suggests that expansion out of Africa occurred twice and caused the genetic extinction of existing populations, with the colonisers later diversifying into separate races.

What about races?

But Templeton said this extinction never happened and a combination of movement and interbreeding meant diversification of races didn't occur.

"We really have to abandon the idea of race. It actually does not reflect the genetic differences we can now measure in an objective fashion."

Templeton said the differences between human populations today were based on geography not genetics.

This meant a Norwegian would be more closely related than a Fijian to someone from sub-Saharan Africa.

"We do see differences in different regions of the world but the best indicator of those differences is simply geographical distance and not things like skin colour."

Templeton said his data was inconclusive on whether interbreeding also occurred with Neanderthals.

But he said there was fossil evidence that this probably occurred, which would imply a bit of Neanderthal could live on in us all.

Australian geneticist Associate Professor Philip Batterham from the University of Melbourne said the research showed humanity was far more closely related that previously thought and that race was a cultural phenomenon.

Templeton's research was published in the journal Nature in March 2002.

[Varda]

If inbreeding were truly the cause of low aptitudes in Cockers then Border Collies, another purebred, couldn't possibly be the dogs with the highest aptitudes since inbreeding is the method of maintaining all purebreds. The reason Cockers are dumb is because of the traits selected in breeding stock. It's the same reason BC's are smart.

[PoorMuttly]

So THAT'S what it is.

I have a TOWEL on my head !!!!!

[Happy2BMe]

Okay - sound good to me. So why don't they start breeding some smarts into Cockers?

[Varda]

I just finished reading a book called "The Journey of Man" by Spencer Wells a geneticist from Oxford who once worked under Luca Cavalli-Sforza. He claims that the genetic evidence is showing a very recent exodus from Africa for all modern humans (60-50,000 ya). He claims work just completed on the Y chromosome has now complemented work done on mtDNA to show no admixture of modern human genes with any other population.

[mikegi]

There are several different genes controlling eye color; some are dominant and some are recessive. You get one gene from your mother and one gene from your father.

Well, my eyes are mostly bloodshot. Where did I get that trait???

Anyway, my father is blond haired, blue-eyed and my mother was brown hair, brown-eyed. She obviously was Bb because all three of the children have blue or green eyes. Mine are more silvery-green than anything - like Meg Foster's in "They Live" but not as extreme.

I've always thought that the Holocaust and its aftermath should be studied scientifically. It represented a "shock" to a population that was somewhat different than its surrounding (Middle Eastern Jews in Europe). What I think would be interesting is how a cultural change affects future generations genetically. Not surprisingly, the "Never Again" mentality took hold after the Holocaust and that has to have some effect on the choices Jewish women make in choosing a husband. Do they choose more aggressive men that would be better defenders of them or do they choose less aggressive men because of the disgust with the aggressive Nazis? I guess the mixing with Europeans probably makes any sort of study impossible. Half the Jews I know are blue eyed and many have blondish hair, which would confuse the heck out of Hitler.

[Varda]

Are you kidding?!!! People love cute dumb dogs! It's the smart ones that get into trouble...

[DallasMike]

I lean toward that idea (or some similar idea) myself, plus the notion that the Garden of Eden was a special place not subject to all of the laws of the outside world (animal eating animals, etc.). In other words, I don't believe that the entire earth was the Garden of Eden.

It's pure conjecture, of course, and really doesn't matter in the scheme of things, but it sure would set the wild-eyed, rabid, young earth creationists on fire if they ever saw our posts....

[DallasMike]

Tell the Jewish couple whose child has Tay-Sacks the fact the disease only occurs in Jews is a political construct.

While we're at it, let's tell the white man who can't dance that race is only a political construct.

[DallasMike]

Race is BS and made up by people with a deliberate agenda of their own.

I agree to a point -- race is a genetically identifiable characteristic and something that I find fascinating. However, race doesn't matter. My new bride is Hispanic (i.e., mixed race) while, as far as I know, I am of purely northern European heritage. We see ourselves as human children of God with slightly different skin coloration.

No one cares about our "mixed marriage" except the liberals. We both have black hair and brown eyes but her skin is several shades darker than mine. Big deal. She looks like a hot tamale while I'm boringly white so I'm very fortunate.

By the way, do you look like Colin Powell? I think that the offspring of "mixed marriages" are often incredibly attractive people. Ethiopia is an entire country of mixed race and 90% of the women there could be supermodels.

[cyborg]

On the level of genetics and anthropological research sure there are slight differences. Hehehe no I don't look like Colin Powell but one of my good friends from Barbados does.
My pic is here http://www.freerepublic.com/~cyborg/ go all the way to the bottom and I'm not the chick on the left either ;-)

[DallasMike]

You are certainly correct that the offspring of people of different races are of mixed-race and not of a presumed inferior race.

Exactly. I believe that within 200 years, the concept of race will be largely gone and we'll all look pretty much alike. Travel makes mixing much easier, plus marrying a person of a different race is no longer a social or political negative in many places.

I dated a beautiful first-generation Norwegian from the midwest about 15 years ago whose grandfather got incensed when she had a Swedish boyfriend in high school. To him, a Norwegian dating a Swede was a mixing of the races and, thus, a bad idea. Attitudes have really changed over the years!

[DallasMike]

My pic is here http://www.freerepublic.com/~cyborg/ go all the way to the bottom and I'm not the chick on the left either ;-)

Hubba, hubba! You prove my point!

[cyborg]

Race as it is discussed between scientists is a very different discussion. I would prefer to discuss with scientists whatever ideas they have to offer. However, since the majority of people are NOT scientists, race is really a political discussion and it is a social construct. Were politics left up to evolutionary biology we would still all be equal anyway since according to the theory of evolution we all share a common ancestor. It's all up in a lot of people's minds and as usual LIBERALS are the biggest racists and fixators on race there is.

[cyborg]

hehehe :blushing:

[megatherium]

I guess the mixing with Europeans probably makes any sort of study impossible. Half the Jews I know are blue eyed and many have blondish hair, which would confuse the heck out of Hitler.

There's been some work done to trace the genetics of Jewish people. The Ashkenazim (European Jews) do appear to be largely European genetically, but I gather there are genes that tend to be found only in them and not in other Europeans. Can't remember the details.

[Smartass]

[TontoKowalski]

Many scholars of the Bible think there are at least two creations of man, the sixth day man, made from gray dust, told to hunt, gather, and have dominion, and the creation of "Adam" sometime after the Sabbath rest, whose name means "red earth", able to blush, whose different command from God was to farm or till the earth.

Hon, what Bible are you (or those scholars) reading?

If you are that gullible and have any money whatsoever, please let me know so that I can concoct some wild fantasy and pass it off as truth, thereby separating you from your fortune.

[DallasMike]

Race as it is discussed between scientists is a very different discussion.

Agreed. My degrees are in chemistry and chemical engineering so, while I'm not qualified in biology, I still take a very scientific view towards race. It's a fascinating subject.

I think that the whole idea of inferior races is hogwash, of course, because of my Christian belief system, which is backed up by science. We're all human and we're all God's creation.

I also believe that real instances of racial discrimination are fairly rare these days, despite what the Jesse Jackson's of the world say. I don't know a single person who holds racist views. They're out there, I'm sure, but few hold positions of any authority.

[zimdog]

"I agree to a point -- race is a genetically identifiable characteristic and something that I find fascinating. However, race doesn't matter."

---

While I agree that race doesn't matter, I would also say that race itself is not exactly a genetically identifiable charaterstic. Racial categories are defined by people (including Norwegian grandfathers) and these categories change over time. While there are identifiable genes for, say, broad noses or pale skin or curly hair, race is not based on those morphological traits alone. Humans decide why a dark-skinned, curly-haired person with a broad nose (say, a Congolese man) is of a different race than a dark-skinned, curly-haired person with an aquiline nose (say, an Ethiopian man), a pale-skinned, curly-haired person with a broad nose (say, a Greek man) or a dark-skinned, straight-haired person with a broad nose (say, a Paupua-New Guinean man), etc... We've already surpassed the alleged "three races" because people want to distinguish among themselves. The morphological categories are genetically uncomplicated. If people insist on the validity of "race" it would be far more useful, from the scientific community's point of view, to define races genetically. There was an article on this in Discover (the popular science magazine) 10-15 years ago. It said that genetically, you get some strange classifications that cut across all common geographical, cultural and morphological lines, pointing to the fundamental unity of humanity.

But I'm not saying anything you don't know here.

Maybe here:

"Ethiopia is an entire country of mixed race and 90% of the women there could be supermodels."

---

Well, 90% of the population would make Addis a Mecca for young men worldwide ... but must say I like going to Ethiopian restaurants for many reasons, not all of them food-related!

[cyborg]

David Bowie would agree ;-)