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New Skull Analysis Gives Information About Gene Pool

14.02.2006


Despite success of molecular genetics that developed efficient methods for educing mitochondrial DNA from fossil bones, anthropologists prefer primary sources as before and keep investigating skulls. Each skull possess multitude of distinctive and well-perceptible signs: these are supplementary and fontanel bones, sutural bones (epactal ossicle), accessory and inconstant orifices, appendices and protuberances.



As peculiarities of the skull structure are genetically determined, the set of signs allows to judge about the genotype of its owner, and the frequency at which some feature is found reflects genetic peculiarities of the population. In this case, the idea about genetic diversity of populations including the fossilized ones, and about their kinship may be compiled without resorting to molecular methods, thus making the process much easier and less expensive. But will this information be trustworthy?

In various anthropological museums, researchers collected and described 3,475 skulls of representatives of 62 nations of the world. The analysis was carried out based on 35 signs. The obtained level of inter-ethnic diversity is comparable with the already known level of genetic diversity, therefore, signs of skull bones structure represent a trustworthy source of information that is particularly precious in the cases when only bones remain from studied nations.


As characters of skull bones reflect genetic processes taking place in the populations, these signs may be used to reconstruct the ancient populations’ gene pool, to track their kinship ties with each other and with contemporary ethnoses. Thus, it has turned out that the Baikal area was populated during the Stone Age by the people that differed from each other no less than, for example, contemporary Eskimos from Tuvinians.

However, averaged skull characteristics of ancient and contemporary Siberian inhabitants testify to their undoubted kinship. This conclusion was later fully confirmed by the analysis of mitochondrial DNA of contemporary and fossil populations. There is no doubt either about genetic commonality of ancient and contemporary Armenians.

Contemporary ethnoses can be divided into four main groups based on the skull classification: Australo-Negroids, Europeoids, Mongoloids of Siberia and populations of the South-Eastern Asia, where two groups of American Indians adjoin. This classification is rather close to the genetic one both in terms of the content of big groups and sequence of their division. However, one significant distinction does exist: geneticists always separate African and non-African people, whereas skull structure make inhabitants of Eastern Africa related with aboriginal population of Australia. As the majority of investigated signs did not depend on geographical coordinates or climatic peculiarities of the region, skulls similarity cannot be explained by external actions. Probably, it reflects the traces of ancient migrations into Melanesia from Eastern Africa. According to the latest archeological data, populating of Australia by human beings started no later than 60 thousand years ago. And molecular geneticists believe that first migrants went away from Africa not northwards but along the coast of South-East Asia. So, skull analysis results fully agree with existing hypotheses.

It might be certainly that emergence of new paleogenetic and paleoanthropological data will change more than once our notions about routes and stages of mankind settling. At this phase, other thing is fundamentally important – analysis of certain characteristics of skull structure allow to recreate the picture of racial differentiation and to judge about kinship ties between different ancient and contemporary populations of human beings.

| alfa
Further information:
http://www.informnauka.ru

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