Scholars have long debated the exact origins of our species. Some have maintained that modern humans probably arose simultaneously in several regions of the globe. They base these arguments largely on the fossil record, which shows that some of our immediate predecessors¿Homo neanderthalensis and Homo erectus, for instance¿had migrated out of Africa as early as two million years ago. But a new study published in today's issue of Nature lends more credibility to the rival theory¿namely that Homo sapiens emerged only in Africa, and only later infiltrated other regions, wiping out the Neanderthals already living there over time.
Instead of tracking our family tree with fossils, the study's authors¿Ulf Gyllensten and Max Ingman of the University of Uppsala, and Henrik Kaessmann and Svante P¿¿bo of the Max Plank Institute for Evolutionary Anthropology¿turned to the living. They completed the most extensive analysis of mitochondrial DNA (mtDNA) ever done, taking samples from 53 people having diverse geographical, racial and linguistic backgrounds. Unlike the DNA within chromosomes, which is inherited from both parents and so changes slightly with each generation, mtDNA is passed directly from mother to child; only random mutations alter its sequence. As a result, it offers a powerful measure of how closely different populations are related.
Earlier work on mtDNA had focused exclusively on the control regions of the sequence, which account for a scant 7 percent of its total. In contrast, Gyllensten and his colleagues worked out the entire mtDNA sequence¿a string of some 16,500 base pairs¿for each individual in their study. From this data, they weeded out stretches of DNA that had mutated unusually quickly and so very likely represented little more than twigs on the family tree. When they compared the rest, a trunk and major branches became clear: the most recent common ancestor of all subjects in the study lived in sub-Saharan Africa some 171,500 to 50,000 years ago, suggesting that we are all descended from a single group there. In addition, they found a major branch separating most Africans from non-Africans, which probably represents H. sapiens' first major exodus from the continent, 52,000 to 27,500 years ago.
See what we're tweeting about
6 Comments
Add CommentA refutation: MODERN HUMANS DID NOT START THEIR LIFE IN AFRICA.
Reply | Report Abuse | Link to thisEvidence points to early presence of humans in continents other than Africa. Even the present study, based on bones and DNA comparisons, did not consider all facts, especially facts derived from study of language origin or the testimony from oil reserves.
Bones We should first of all notice that Egyptology reveals serious efforts in Africa as far as conservation of corpes is concerned. This explains why the fossil record in Africa can mislead modern interpreters. It is also noteworthy that bones, though solid in appearance, have a spongelike structure. When exposed to variation of temparature over long time periods, the thousands of tiny holes in the bone structure can give way to the physical process of widening. Thus, bones used for study have been slightly, but steadily deformed over the ages.
DNA To achieve a comprehensive study, DNA vertical comparison (DNA from people that lived in early years of human history and DNA from people that live today) should be completed by DNA horizontal comparison (DNA from contemporaries living in different climatic regions). In that line of reasoning, it is interesting to notice that an individual from northern Europe can be genetically closer to an individual from west Africa than to another individual from northern Europe. DNA being a criteria at individuals level, cannot be used to explain the alleged evolution of species.
Language Scholars studying origin of languages strongly point to the plains of Shinear (Middle East) as the common origin of human languages.
Oil reserves It is known fact that crude oil is the product of compression and heating of ancient organic materials over extended time periods. Therefore, Asia coming first as far as oil reserves are concerned shows that most ancient presence of life can be traced in Asia.
To conclude, I claim human life started on earth when the planet was but one continent. Later on, the earth was basically divided in just 2 totally separated areas: the Americas and the rest (leaving aside isles). Movements from Africa to Asia, then to Europe have always been possible through continental ways. The American Indian found themselves on the other side when the earth was divided (see the historical account of the Bible in the Book of Genesis, chapter 10, verse 25). Thus, these are the only humans that could be naturally isolated.
THE REHABILITATION OF RADIOCARBON DATING
Reply | Report Abuse | Link to thisDating methods using carbon-14 show human species to be younger than expected by evolutionists (6 000 years old). Concerning division of pangaea into various continents, it happened even later (4 000 years ago).
Some would claim the amount of carbon-14 found in ancient human remains is so low that it cannot ensure accurate dating. Still, radiocarbon dating is considered most accurate for youngest remains.
Moreover, evidence points to a 30% maximum difference between carbon-14 proportions found in all human organism remains. Therefore, the method is appropriate for determining global human age.
Furthermore, the 30% ratio shows more than 2/3 of the carbon-14 ever produced in upper atmosphere has not yet been disintegrated. It follows that the decay process started some 4 000 years ago. Therefore, cosmic rays could not strike Nitrogen before 2 000 BCE.
This fact endorses the Bible account in the Book of Genesis, mentioning waters above the expanse (atmosphere or firmament), a solid blue glassy sea made up of huge, congealed cloudy masses, compact enough to be supported by the atmosphere.
Nevertheless, 4 000 years ago, these floodgates of the heavens were released in order to deluge a wicked world, leading to subsequent dislocation of pangaea and surviving righteous human family being scattered over the surface of the earth.
The vast gulf between this writer's understanding of history, and a truly learned understanding, is as wide as the gulf between the whole of human history compared to the time of the contenents' separation. Therefore a reasonable reply would be an impossible waste of time.
Reply | Report Abuse | Link to thisDo any of these people really READ AND UNDERSTAND this magazine, Scientific American? I would think that if a person received every issue and tried to read it with an open mind, he/she would soon come to the conclusion that the time frames and basic premises of the Bible are a myth.
Reply | Report Abuse | Link to thisThe new strategy is obviously to use 'scientific arguments' against science. Quite obviously it is scientifically impossible to prove that the world came to be 4000 BC. What about the cosmological constant, quasars and the age of the sun, for example?
Reply | Report Abuse | Link to thisI thought you were serious, but when you mention the book of genesis i regret the loss of my time reading you.
Reply | Report Abuse | Link to this