Posted on 03/17/2008 8:35:50 AM PDT by blam
Out of Africa, Not Once But Twice
Jennifer Viegas, Discovery News
Out of Africa
March 14, 2008 -- Modern humans are known to have left Africa in a wave of migration around 50,000 years ago, but another, smaller group -- possibly a different subspecies -- left the continent 50,000 years earlier, suggests a new study.
While all humans today are related to the second "out of Africa" group, it's likely that some populations native to Israel, Jordan, Lebanon, Syria, Australia, New Zealand and Indonesia retain genetic vestiges of the earlier migrants, according to the paper's author, Michael Schillaci.
Schillaci, an assistant professor in the Department of Social Sciences at the University of Toronto, also found the earlier group of emigrants had some genetic similarity to Neanderthals, a hominid that left Africa much earlier, settling in Europe and parts of western and central Asia.
"This could be the byproduct of limited [interbreeding] with Neanderthals, or a shared more recent common ancestry with Neanderthals," he told Discovery News. "Humans and Neanderthals share a common Homo ancestor in Africa at around 500,000 years ago. However, Neanderthals evolved in Europe, while modern humans evolved in Africa."
For the study, he calculated genetic similarity by comparing measurements of the cranium, the part of the skull that encloses the brain. In addition to actual DNA testing, researchers often use such skull measurements to establish relationships between ancient human groups.
Schillaci examined fossils representing at least 28 modern and prehistoric human populations.
The earliest known individuals from the Near East, he found, were genetically similar to the earliest individuals from Australia, New Zealand and Indonesia. All modern-day humans are more similar to Europeans who lived between 40,000 and 10,000 years ago -- after the second wave from Africa.
"The most likely explanation...is that the expansion out of Africa that was ancestral to the early Australasians occurred before the well-accepted expansion at around 50,000 years ago that led to the colonization of Europe," he said, adding that the first populations out of Africa were later "swamped genetically by the subsequent larger expansion." Based on the findings, which have been accepted for publication in the Journal of Human Evolution, he concludes the first human group to have left Africa "may well have been a separate subspecies" of modern human.
Prior research could support that contention. At an Ethiopian village called Herto, archaeologists recently found fossils of individuals who were more robust than modern humans. They date to 154,000 to 160,000 years ago.
Erik Trinkaus, a professor of physical anthropology at Washington University in St. Louis, thinks the new paper "is an interesting analysis," but he told Discovery News that he hopes it will be redone with more fossils, "a better set of measurements and with the caveat that there is a huge (time) gap between his relevant samples."
Schillaci neglected one of the earliest known Southeast Asian humans in his study, noted Trinkaus.
This individual "predates the Australian fossils and is the only relevant fossil that we have between Israel and Indonesia for the relevant time period," he explained, adding that "we have no relevant fossils between 100,000 and 30,000 from the Levant [Near East] and Australia to sort out what might have been happening there."
Chris Stringer, a paleontologist at the Natural History Museum in London, however, expressed fewer reservations.
"This is a very interesting and important study that provides much food for thought," Stringer told Discovery News. "It revisits in more detail and with new approaches something which several researchers have previously noted -- certain early modern samples...seem closer to very early H. sapiens in Israel and Africa than to other early modern samples around the world."
Stinger isn't yet convinced that the Ethiopian fossils and early Australian/Indonesian individuals provide evidence of a new human subspecies. The rigors of dealing with prehistoric life might have simply resulted in sturdier bodies.
Also, everyone outside Africa are more related to themselves than anyone in Africa.
This explains my high school gym coach...
http://www.freerepublic.com/focus/f-news/1987022/posts
At some point in time these two storied/systems are going to meet.
There WREN'T any modern humans 50K years ago; in all likelihood there weren't even any neanderthals around that long ago. Entire article is garbage.
Do you have any evidence to support your rant?
Modern humans are 200,000 years old.
Although it is still possible that the entire article is garbage, but not for the reason you suggest.
Not by the cars they drive but by humanoid characteristics that are in common with 21 century mankind.
Image: JOHN GURCHE PORTRAIT OF A PIONEER With a brain half the size of a modern one and a brow reminiscent of Homo habilis, this hominid is one of the most primitive members of our genus on record. Paleoartist John Gurche reconstructed this 1.75-million-year-old explorer from a nearly complete teenage H. erectus skull and associated mandible found in Dmanisi in the Republic of Georgia. The background figures derive from two partial crania recovered at the site.
She actually makes Hillary look attractive.
So it was a liberal.
The Neandertal EnigmaFrayer's own reading of the record reveals a number of overlooked traits that clearly and specifically link the Neandertals to the Cro-Magnons. One such trait is the shape of the opening of the nerve canal in the lower jaw, a spot where dentists often give a pain-blocking injection. In many Neandertal, the upper portion of the opening is covered by a broad bony ridge, a curious feature also carried by a significant number of Cro-Magnons. But none of the alleged 'ancestors of us all' fossils from Africa have it, and it is extremely rare in modern people outside Europe." [pp 126-127]
by James Shreeve
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Thanks Blam. Didn't we have a topic like this a month or so ago? |
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The link in post #3?
Oh, well, if you’re gonna point out the obvious... ;’) Thanks blam.
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