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Human mitochondrial molecular clock : ウィキペディア英語版 | Human mitochondrial molecular clock The human mitochondrial molecular clock is the rate at which mutations have been accumulating in the mitochondrial genome of hominids during the course of human evolution. The archeological record of human activity from early periods in human prehistory is relatively limited and its interpretation has been controversial. Because of the uncertainties from the archeological record, scientists have turned to molecular dating techniques in order to refine the timeline of human evolution. A major goal of scientists in the field is to develop an accurate hominid mitochondrial molecular clock which could then be used to confidently date events that occurred during the course of human evolution. Estimates of the mutation rate of human mitochondrial DNA (mtDNA) vary greatly depending on the available data and the method used for estimation. The two main methods of estimation, phylogeny based methods and pedigree based methods, have produced mutation rates that differ by almost an order of magnitude. Current research has been focused on resolving the high variability obtained from different rate estimates. ==Rate variability== A major assumption of the molecular clock theory is that mutations within a particular genetic system occur at a statistically uniform rate and this uniform rate can be used for dating genetic events. In practice the assumption of a single uniform rate is an oversimplification. Though a single mutation rate is often applied, it is often a composite or an average of several different mutation rates.〔 Many factors influence observed mutation rates and these factors include the type of samples, the region of the genome studied and the time period covered.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Human mitochondrial molecular clock」の詳細全文を読む
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