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Molecular anthropology
Id 0633  +
Kieli englanti  +
Kirjoittaja Markku Niskanen +
Otsikko Molecular anthropology +
Has queryThis property is a special property in this wiki. Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology + , Molecular anthropology +
Categories Demography  + , Articles in English  + , Ethnicity and physical anthropology  +
MuokkausaikaThis property is a special property in this wiki. 30 joulukuu 2014 15:14:06  +
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TekstiThis property is a special property in this wiki. <P align="justify"> In Europe, molec<P align="justify"> In Europe, molecular anthropology is generally used to refer to a new departure in genetic research which has come to be employed alongside archaeology and historical linguistics in investigating the origins of peoples. European molecular anthropologists typically come from evolutionary biology and medicine. In the United States, molecular anthropology has been used since the 1960s to refer to a special branch of physical (biological) anthropology in which population genetics is applied to investigating the molecular evolution and genetic variation of the human race. American molecular anthropologists are thus typically physical anthropologists who have trained in schools of anthropology and who in addition have a competence in cultural anthropology, archaeology and linguistics.</P> <P align="justify"> Molecular anthropological research can be claimed to have started when scientists began to compare the frequencies of ABO blood groups (A, B, AB and O) in different human populations soon after the First World War. The discovery of the structure of the DNA molecule in the 1950s led to an increase in the interest of physical anthropologists in research at the molecular level. In the 1960s, serological research displaced phenotypical investigations in explicating the genetic relations between different human populations. In the same decade, comparisons began between humans and other primates with respect to the amino acid sequences of haemoglobin, and molecular research into human evolution and variation began to be called molecular anthropology.</P> <P align="justify"> Molecular anthropology has benefited greatly from the breakthrough in genetic engineering that began in the 1980s, and which since the late 1990s has permitted a direct genetic comparison between present-day humans and fossilized remains, such as those of Neanderthal humans, which are tens of thousands of years old. At the moment, the major problem for molecular anthropological and other genetic research is the fact that genetic engineering has developed faster than theory. This could easily lead to misinterpretation of the results that are obtained from it.</P> <P align="justify"> The scope of molecular anthropological research today is very broad. Some molecular anthropologists study the genetic relations between man and other primates (anthropoids, apes and lemuroids), the genetic structures of human and other primate populations, the microevolution of the human race (changes in the genetic structure of a population from one generation to the next), the genetic relations between peoples, or the origins of peoples and the DNA of archaeological finds of individuals. Others may for example use genetic paternity tests to ascertain which of the males in a group of chimpanzees is the father of which children, or they may carry out forensic anthropological work by examining the DNA isolated from the bones of the skeleton of an unknown corpse in order to ascertain its identity. Molecular anthropologists investigate the origins and the relationships between populations through a study of DNA. The differences in DNA sequences between populations in those parts of the DNA that do not carry genetic coding are more reliable indicators of genetic relationships between populations than selective phenotypical features and the genes that affect them. Therefore, molecular anthropological research is moving away from the so-called classical indicators of cellular DNA (e.g. the comparison of blood groups) to the study of microsatellites (DNA). These so-called tandem copies comprise the majority of DNA, they are neutral with respect to selection, and they have a relatively high incidence of mutation. The DNA of the cell nucleus is used mainly in estimating the genetic distances between different populations. </P> <P align="justify"> Molecular anthropologists are particularly interested in mtDNA and Y-DNA because the former permits the elucidation of the origins of female ancestors and the latter of male ancestors, and consequentlyit is possible toreconstruct ancient migrations. The family tree of maternal lines has been reconstructed to a common original form (a mitochondrial eEve f), and that of paternal lines to their common original form (an eAdam f). Contrary to common belief, these original forms did not necessarily belong to the last common original mother and father of all human beings because mtDNA and Y-DNA are particularly susceptible to genetic drift (chance). The maternal line vanishes if the woman does not have any daughters, and the paternal line if the man has no sons.</P> <P align="justify"> Genetic drift is most likely to take place when a population goes through a so-called genetic bottleneck. This happens, for example, when a group becomes detached from the main population and migrates elsewhere. The descendents of these so-called efounders f have a random collection of the paternal and maternal lines in the original population. A population also passes through a genetic bottleneck when it rapidly decreases in size. In such a situation, rare maternal and paternal lines (and their nuclear DNA indicators) can easily disappear.</P> <P align="justify"> Although mtDNA and Y-DNA provide more information about ancient migrations because of the founder effect, nuclear DNA is a more reliable indicator of genetic relationships between peoples. This is because of the greater vulnerability of mtDNA and Y-Dna to genetic drift and also because in most communities a woman moves into the home of her husband when she marries. Neighbouring populations which have exchanged genes over many generations, but which have separate origins, typically have many of the same maternal lines and few of the same paternal lines, and the genetic distances calculated on the basis of nuclear DNA indicators show that they are genetically close to each other. Therefore the origins of peoples and the relationships between them should not be reconstructed on the basis of mtDNA alone. Molecular anthropological research will in the coming years provide more exact information about the molecular evolution of the human race and about the origins of peoples and the relationships between them. Our knowledge about Y-DNA variation in particular will increase. </P> [[Saami in the light of population genetics|Population genetics]] <BR> [[DNA research|DNA research]]<BR><BR> [[Table of contents: Demography, ethnicity and physical anthropology| Table of contents: Demography, ethnicity and physical anthropology]]<BR><BR>hysical anthropology]]<BR><BR>  +
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