Fresh debate over human origins

The theory that we are all descended from early humans who left Africa about 100,000 years ago has again been called into question.

US researchers sifting through data from the human genome project say they have uncovered evidence in support of a rival theory.

Most scientists agree with the idea that our ancestors first spread out of Africa about 1.8 million years ago, conquering other lands.

The prevailing theory is that a second exodus from Africa replaced all of the local populations, such as Europe's Neanderthals.

Some anthropologists, however, advocate the so-called multiregional theory, that not all the local populations were replaced.

They think some of these ancient people interbred with African hominids, contributing to the gene pool of modern humans.

The new evidence, published online in the Proceedings of the National Academy of Sciences, is based on an analysis of data from the human genome project - the effort to map the entire human genetic blueprint.

Researchers led by Henry Harpending, professor of anthropology at Utah University, studied small differences in human DNA known as single nucleotide polymorphisms.

Studying when these mutations appeared gives a window into the ancient past, allowing scientists to trace the rise and fall of early humans in different parts of the world.

"The new data seem to suggest that early human pioneers moving out of Africa starting 80,000 years ago did not completely replace local populations in the rest of the world," he says. "There is instead some sign of interbreeding."

The study suggests that there was a bottleneck in the human population when ancestors of modern humans colonised Europe about 40,000 years ago.

This is a puzzle because earlier human genetic studies have backed the idea that a rapidly expanding African population spread globally and replaced all local populations.

One possibility is that there was limited interbreeding between humans migrating from Africa and local populations in Europe and elsewhere.

Commenting on the research, Professor Chris Stringer, Head of Human Origins at London's Natural History Museum, said that in the last few years the multiregional model of human evolution had been called into question by new data, much of it genetic, showing our species had a recent African origin.

He told BBC News Online: "Arguments now centre on whether we are recently and entirely Out of Africa, or just mainly so.

"Some replacement models, and some genetic data, suggest no interbreeding at all with archaic peoples outside of Africa, while other replacement models allow limited interbreeding with the locals over the short time scale in which they overlapped.

"This new research suggests there could have been some interbreeding, but as the authors recognise, it could have been limited, and whether it happened at all is still an open question."

To: f.Christian

Sorry this took awhile to respond too christmas functions drew my attention. What do I base my life on? What am I required to base it on? My life doesn't need a base outside of myself to be fullfilled. Even if i didn't base my life on rational thought I would still not need a basis to be complete. You seem to need the support of a mythology to help you overcome life's problems I do not. Your life may not be complete without a savior to fill you with hope. I need no false hope I am complete unto myself. Even if every man woman and child on this earth believed in Christ I would have no need. I do not need the consensus of the community.

I search for rational truth because that is where reality resides. Truth is not subjective, truth is not objective, and Truth is not subject to the varied Mythologies of this Planet many of these mythologies being much older than the one you embrace. Truth is absolute. That is why in the search for an absolute truth you must often throw off the weak beliefs of degenrate religion or even the hard won beliefs gained from personal insight. Truth cares for none of that.

God is not truth God is a crutch for those to weak to cut away the dead limbs, shoot the sick dog, or take that first unaided step into the light of reason.

47 posted on 12/22/2002 3:46 PM PST by Sentis

To: Sentis

I thought so!

48 posted on 12/22/2002 3:50 PM PST by f.Christian

Who decreated God...

Commie--Junk science...

"That's the case with the Darwinists in the United States. The majority of the people are skeptical of the theory. And if the theory starts to waver a bit, it could all collapse, as Napoleon's army did in a rout."

"They have... lost(link)---a big one."

"They're like Napoleon's army in Moscow. They have occupied a lot of territory, and they think they've won the war. And yet they are very exposed in a hostile climate with a population that's very much unfriendly."

Do you need an explanation of these thoughts...article---I have one!

I noticed on another post of yours you seem to think 'democracy' is the all and all.

Good News For The Day

‘The Sabbath was made for man, not man for the Sabbath’ ( Mark 2:24)

"Except for God himself, there is nothing in the practice of religion that is more sacred than humanity. Men and women lose their dignity under any regime that sanctifies anything above men and women."

"In Communism, and Fascism the... system---is everything. The individual is subservient to the plan; to the state."

"Years ago a novelist, Barbara Goldberg wrote:"

"You see that bridge; that huge red naked thing of steel? Magnificent eh?
And there-no, there, right at the top. A little dot that sways and crawls along,
fearful lest it lose its dizzy head, and dash into oblivion. Pitiful isn't it?
That pygmy being with its two small hands, and smaller brain,
you see him? Well, he made the bridge!"

"People are greater than things. They are not like bridges; they build them! It is therefore as it should be, that God, when he sought to reveal himself to the world, did so through a human personality-the noblest thing in all creation. Not only were human beings honored by the incarnation, they were dignified by Jesus' own treatment of his fellows. Habitually he reserved his kindest attentions to human life in its frailest forms. Jesus gave the world a spiritual perspective that every religious obedience secondary, to our duty to care for one another."

By James Jacobs from http://www.jqjacobs.net/anthro/paleo/multiregional.html

Multiregional Evolution

In the same issue as Wilson and Cann presented the 'Out of Africa 2' or 'Eve Hypothesis' Alan G. Thorne and Milford H. Wolpoff argued the polygenic or multiregional side of the modern human origins debate. They maintain that there is no single recent dispersal for modern humans, that humans originated in Africa and then slowly developed their modern forms in every area of the Old World. They also argue that the molecular geneticists' view must be rejected because their reasoning is flawed. Here follows a summation of their arguments.
According to the multiregional view mtDNA is not our only source of evidence. Fossil remains and artifacts represent a much more reliable and a monumental body of evidence. Multiregional evolution traces all populations to humans first leaving Africa over 1 mya (now known to be about 1.8 mya). Today distinctive populations maintain physical differences. The features that distinguish Asians, Australian Aborigines and Europeans are said to have evolved over a long period where these peoples are found today.

Thorne and Wolpoff argue that the fossil record, stretching back for a million years, is the real evidence for human evolution. Their self-described goal is "to describe a theory that synthesizes everything known about modern human fossils, archaeology and genes." They outline their own five predictions of the Eve theory, that modern humans from Africa completely replaced all other groups, that the earliest modern humans appeared in Africa, therefore that the earliest modern humans in other areas should have African features, that modern humans have never interbred, and that an anatomic discontitiuity should be evident.

The claim that a replacement could occur rapidly in every climate and environment is unprecedented from their 1992 viewpoint. At the time of their writing the volcanic winter bottleneck scenario was not yet presented. The authors point out that if replacement occured we would expect to find archaeological traces, yet we can find none in Asia.. The hand ax was common in Africa, yet the technologies of eastern Asia did not include handaxes before or after the African dispersal period. Artifacts found in the earliest assemblages continue to appear into the very late Pleistocene.

The hominid fossils from Australasia are argued to show a continuous anatomic sequence, with the earliest Australians displaying features seen in Indonesia 100,000 years ago. Similar evidence is seen in northern Asia. One million years old Chinese fossils differ from Javan fossils in ways that parallel the differences between north Asians and Australians today. Morphological continuity is also evidenced by prominently shoveled maxdlary incisors occurring in high frequency in living east Asians and in all the earlier Asian fossils. They point out the fact that the Neandertals and modern humans in the Near East shared an identical culture. They also argue that the Neandertals were not fully replaced. The more recent DNA isolation from Neandertal fossils counters this belief.

Thorne and Wolpoff also cite the potential for genetic drift, that some mtDNA disappears every time a generation fails to have daughters. Each lost branch alters the estimation of coalescence to a more recent date. Population size is also addressed, especially the shrinking of population in the Northern Hemisphere due to the Ice Ages. Reductions exacerbate genetic drift and loss of mtDNA types. Therefore, they contend, the lengths of mitochondrial lineages does not actually reflect the age of their divergence. They also criticize the dependence of the Eve model on a molecular clock as unreliable.

Finally, it is affirmatively argued that the close genetic similarities of the entire human race reflect linkages between people, an ancient history of population connections and mate exchanges, or, in other words, gene exchange.

Source:

Thorne, Alan G. and Milford H. Wolpoff. 1992. The Multiregional Evolution of Humans. Scientific American 266:76-83.

"The creation vs. evolution... drama(link)---continues."

"From here it looks like the God people are slowly winning. When you think about that, it's a logical outcome. A supreme court that opens up with a prayer comes off as a bit hypocritical when it says that religion has no place in publicly-financed institutions. That's a bit like a fox passing a law against hawks eating chickens. It is fascinating to watch as this conflict proceeds in America. In the media, the battle is portrayed as the forces of rationality and logic (science) against the forces of irrationality and ignorant bigotry (religion). Like everything else the mainstream media tells you, this description is a load of crap."

"The truth of the matter is that Galileo wasn't put under house arrest because he denied the Copernican system. Except for Genesis, which is a dynamite scientific treatise on the evolution of the universe and life on earth, the bible doesn't say a damn thing about astronomy. Comets as portents, and that Shakespeare sort of thing, yes, but other than that, it leaves the subject for other publications. The Catholic Church of Galileo's day had a number of officials who were proponents of the sun-centered point of view. Science wasn't their problem. Their problem was arrogance of another kind. Like professors in modern American universities, they thought their behinds should be kissed on a regular schedule. It wasn't what Galileo said that got him into trouble, it was the way he said it."

"He wasn't... politically---correct"(...original source/article).

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