Title: Mitochondrial DNA Polymorphisms and Anthropology
Abstract: Although there is 'a human mtDNA sequence' of 15.56 kb, a very large number of sequence polymorphisms have been found in the human population. Replication of mtDNA is thought to be error prone, and hence mtDNAs represent a "molecular clock" running faster than the nuclear clock. The absolute rate of the clock and its variation at different loci is still much debated. Sequence polymorphisms can be tolerated in structural genes because of the high degeneracy of the mitochondrial genetic code, or because mutations result in conservative amino acid substitutions. There is also a region (the D-loop, ∼1.2 kb) that contains short specific elements for initiation of transcription and replication, but is otherwise free of coding sequences for mRNA, tRNA or rRNA. Sequence polymorphisms in this region are particularly frequent, and the region is easily analyzed after amplification by PCR. Two major problems have been addressed by phylogenetic analyses of human mtDNAs: 1. the origin of humans, and their relationship to the surviving hominoid apes; 2. the relationship of existing human ethnic groups, subpopulations and tribes to each other, and their geographical dispersion over the inhabitable areas of the earth. A consensus is emerging that all present-day humans (Homo erectus) are descendents of a group migrating out of Africa into the Middle East within the past 80,000– 200,000 years. There are also significant sequence polymorphisms within a single subpopulation. These can be utilized in forensic identifications of individuals in pedigrees (with a bone from a deceased providing sufficient DNA), and in other criminal investigations.
Publication Year: 1999
Publication Date: 1999-06-21
Language: en
Type: other
Indexed In: ['crossref']
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