Samwik. Why didn't you like my comment:
"But the gene for robustness and species separation doesn't spring up over night."
The mutation probably sprang up overnight but the gene almost certainly wouldn't have. I agree mutations occur in many forms and have complicated results but that's not the point. As I've said before (and been criticised for it), this last idea is a hangover from victorian economic ideas of "survival of the fittest" and biblical ideas of a "chosen" population.
We know from the study of dairy cattle that most mutations give rise to recessive genes. This is just as well or most of us wouldn't have survived our mother's pregnancy. Half the offspring of an individual with a recessive gene will also carry that gene......> But selection cannot act on a single recessive gene. It can only act on double recessives. Double recessives happen through inbreeding. Half the offspring of one double recessive and one single recessive parent will have the characteristic. By that time single recessives could be widely and randomly distributed through the population. This would lead to a rapid expansion of the characteristic. But it's the gene that spreads through the population, not just the element of the population with the characteristic. Other genes in the local population survive. In fact it has been pointed out each gene has a separate ancestor and has its own evolutionary history. A friend calls this the wave theory of evolution..........>
They have simply moved through the human species over the generations, but they behave like dominant genes. For example many Y-chromosome lines have been spread by male population movements such as the Mongols............>
Hope this all makes sense. The fluid speciation of Galapagos finches was covered on another thread.
I have found all the above contributions, most interesting.
Far be it for me to dispute the facts that 'Man Came out of Africa.'
Or even 'Came out of Africa' and found his way to Australia. But there are relatively big genetic distances between Australian Aboriginese, and Sub-Saharan Africans, since the Indian Ocean is in the way. Nor are Aborigines closely related to Europeans, since Asia stands in the way.
My remarks may sound trite, but Aborigines could have come from New Guinea by land bridge or even rafts. Obviously very few came, and were left in isolation.
Nor would I like to say that there was no contact at all, since it is known that prehistoric Southeast Asians rode rafts 4,000 miles across the Indian Ocean to colonize Madagascar.
But I would like to leave Australia, and rather concentrate upon Eastern Asia, and China, and wonder how it could be possible for the "Out of Africa" theory to become reconciled within the time scale of 50k years Out of Africa?
I just cannot believe that within that short time scale, mankind moved from Africa to colonise China?
China has a very ancient history. With some even ancient fossils of early man, at least as old, and in some cases even older that those hominids found in Kenya, Spain, and elsewhere.
I have tried to come up with a Fossil list, thats not in any particular age order, to show that there has not been enough time allowed for mankind to colonise the far East, from Africa.
Australopithecus afarensisThe most famous member of this species is Lucy, an adult female skeleton discovered in 1974 and nicknamed after a Beatles song. Lucy lived about 3.18 million years ago and was fully capable of walking and running on two legs.
Australopithecus africanusAn early descendent of Lucy and lived in Southern Africa between 2 - 3 million years ago. Its brain was larger than Lucy's and its facial features were more human-like.
Paranthropus aethiopicusAn early ape-like hominid, that walked on two legs and lived between 2.8 - 2.2 million years ago. Based on skull measurements, scientists concluded this species had the smallest adult hominid brain ever discovered.
Paranthropus boseiThey split from the line leading to modern human some 2 million years ago and lived alongside our ancestors for millions of years, but seemed to have died out.
Homo habilisThe missing link between the ape-like hominids like Lucy and the more human-like ones that came after? It had long ape-like arms but walked on two feet and was capable of creating crude tools.
Homo ergasterScientists can't decide whether this African hominid is just a failed predecessor of H. erectus or the rightful ancestor of modern humans. It had a thinner skull than H. erectus, but was more proficient at making tools and using fire.
Homo erectusH. erectus is generally believed to be the direct ancestor of modern humans and also the first hominid to live in caves and tame fire.
Homo floresiensisI included this species, since they are diminutive, which could be construed that they are new species of hominid, discovered on the Indonesian island, and therefore unlikely to have "Come out of Africa', so dimunitive?
Cro-Magnon manThey looked fairly identical to modern humans, and lived in Europe between 35,000 and 10,000 years ago. Their cave paintings and sculptures are the earliest known examples of art by a prehistoric people.
Neanderthal manStocky and squat. Neanderthals looked distinctly different from modern humans. But they buried their dead, cared for their sick and injured, and may have been capable of language and music. Scientists recently put together a complete Neanderthal skeleton and are working on the genome.
Peking Man China. -AsiaLived 200k-500k years ago in caves at Zhoukoudian. The bones of Peking Man discovered in the cave in the hill's north face include six complete or relatively complete skulls, eight skull
fragments, six pieces of facial bone, 15 mandibles, 153 teeth, seven sections of broken femur, one broken shinbone, three pieces of upper arm bone, one clavicle and one wrist bone belonging to more than 40 individuals of different ages and sexes.
Pithecanthropus VIII, Homo erectus -AsiaDiscovered by Sastrohamidjojo Sartono in 1969 at Sangiran on Java. This consists of a fairly complete cranium, with a brain size of about 1000 cc. It is the most complete erectus fossil from Java. This skull is very robust, with a slightly projecting face and huge flaring cheekbones. It has been thought to be about 800,000 years old.
The Maba cranium dated to approximately 120,000 years ago was discovered in 1958 in the southern Chinese province of Guangdong. It was the first substantial specimen of a pre-modern form of H. sapiens found in East Asia. It was iniatially thought to be an Asian Neandertal but does not in fact show any of the derived features of Neandertals as known from Europe and the Near East. The Maba skull is similar to other more complete finds of pre-modern H. sapiens subsequantly found in China,
differing only in minor ways, such as the size and shape of the eye orbits and nasal bones. It is similar to the recently discovered 'Narmada' skull from India.
The Liujiang cranium is similar to recently discovered southern Chinese crania dated to the end of the Pleistocene, approximately 10,000 years ago. Cultural remians from the nearby Bailiandong cave site have been dated to approximately 30,000 years before present. It is therefore likely that the Liujiang remains date to the end of the Late Pleistocene, approximately 10-30,000 years ago.
Sorry about the long list, but I am trying to show in my own way that the origin of modern Asian peoples are still a source of controversy in the human Evolution story. Mankind has lived in Asian a very long time. Some of the oldest known fossils of prehistoric man have been found on the island of Java in Indonesia and near Peking in northern China.
The world's oldest civilizations are Asian. Chinese civilization is nearly 5,000 years old, and the civilization of India is nearly that old.
After looking at my very incomplete list, I am certain that these archaic Asians evolved as a separate and distinct line,
alongside the 'Out of African' hominids.
I feel Asians have too many facial, and body-type differences, to have arisen from the same stock?
Furthermore under the Scienceagogo topic entitled "Ancient Cavemans Virus Resurrected" (dated 08-05-2007 below) it seems pretty certain that once a heritable virus attacks ancient humans, -or even modern humans? It can become trapped in the human DNA for all time.
Analogy is - a disease,...that confers resistance to to its host only after attacking it.
Viruses typically infect whole populations, or substantial parts of them, so two members of a breeding pair are very likely to carry the same new instructions. This "ancient cavemans virus" theory, is a possible new way for evolution to advance, very quickly? Pandemic flue, Blackdeath, now dormant, due to large population resistance.
In fact, genes for recessive diseases are are very easy to find -unlike other genes. For instance Tay-Sachs, or Sickle cell, certain form of blindness, different eye colorings, breast cancers, heamophilia, and many more, are easy to trace within families.
Notice, that some of these diseases are non-existant within the Asian population?
Admittedly, I have not researched this line, but I have no reason to believe it is untrue in the main.
The above, does seem to show the possibility that Asians evolved from a separate stock. Since all,...or some some of these recessive genetic diseases, could be carried by a heritable viral genome, which would be noticable within the present Asian population?
I should have included Blood types as a difference as well. Not just the four groups but their 14 sub-divisions as well.
Of course this idea could work back the other way as well. I'm thinking from ancient Asia, back to Aborigine Australia. Since thats the way human movement went.
Do Aborigines have any form of ancient heritable DNA/resistance to Yellow Fever, Chandipura virus, or other ancient Asian virus?
Research will tell.
