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  • alleles
  • In population genetics, fixation is the change in a gene pool from a situation where there exists at least two variants of a particular gene (allele) to a situation where only one of the alleles remains. (wikipedia.org)
  • Genetic drift is the effect of changes in genetic composition of a finite population, due to random replacement of alleles from one generation to the next. (els.net)
  • While any individual can have up to only two alleles, populations as a whole can have hundreds or even thousands of alleles. (biologos.org)
  • In any given generation, the vast majority of the alleles present in a population were inherited from the previous generation - just like a language group learning from their parents, and picking up the language as a whole, but also some of their particular linguistic quirks. (biologos.org)
  • Migration
  • TreeMix by Joe Pickrell and Jonathan uses large numbers of SNPs to estimate the historical relationships among populations , using a graph representation that allows both population splits and migration events. (stanford.edu)
  • These populations were large enough to dismiss significant variation due to drift over the timescale of the study and isolated enough to preclude mass migration. (genetics.org)
  • There is general agreement among anthropologists that the source populations for the migration into the Americas originated from an area somewhere east of the Yenisei River. (wikipedia.org)
  • SNPs
  • Within the Q clade, there are 14 haplogroups marked by 17 SNPs.2009 In Eurasia, haplogroup Q is found among indigenous Siberian populations, such as the modern Chukchi and Koryak peoples. (wikipedia.org)
  • diploid population
  • Haldane's remark alluded to the fact that if an individual loses its life to save two siblings, four nephews, or eight cousins, it is a "fair deal" in evolutionary terms, as siblings are on average 50% identical by descent, nephews 25%, and cousins 12.5% (in a diploid population that is randomly mating and previously outbred). (wikipedia.org)
  • Drift
  • For example, if a population includes allele A with frequency equal to 20%, and allele a with frequency equal to 80%, there is an 80% chance that after an infinite number of generations a will be fixed at the locus (assuming genetic drift is the only operating evolutionary force). (wikipedia.org)
  • F isher and F ord (1947) argued that the population size was too large for the changes in the frequencies to be due to drift and suggested that fluctuating selection must be acting. (genetics.org)
  • He published numerous foundational papers on the effects of mating systems, selection, gene-environment interactions, linkage disequilibrium, and genetic drift on the genetic variation of inbreeding plant populations. (wikipedia.org)
  • A slightly deleterious mutation may not stay in mutation-selection balance but may instead become fixed by genetic drift when its selection coefficient is less than one divided by the effective population size. (wikipedia.org)
  • among
  • Dienekes points me to a new paper, European Population Genetic Substructure: Further Definition of Ancestry Informative Markers for Distinguishing Among Diverse European Ethnic Groups. (scienceblogs.com)
  • Some subclades of C and D closer to the Amerindian subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations. (wikipedia.org)
  • displaystyle
  • Absolute fitnesses can be used to calculate relative fitness, since p ( t + 1 ) = n ( t + 1 ) / N ( t + 1 ) = ( W / W ¯ ) p ( t ) {\displaystyle p(t+1)=n(t+1)/N(t+1)=(W/{\overline {W}})p(t)} (we have used the fact that N ( t + 1 ) = W ¯ N ( t ) {\displaystyle N(t+1)={\overline {W}}N(t)} , where W ¯ {\displaystyle {\overline {W}}} is the mean absolute fitness in the population). (wikipedia.org)
  • Ignoring frequency-dependent selection, the genetic load L {\displaystyle L} may be calculated as: L = w max − w ¯ w max {\displaystyle L={{w_{\max }-{\bar {w}}} \over w_{\max }}} where w max {\displaystyle w_{\max }} is either some theoretical optimum, or the maximum fitness observed in the population. (wikipedia.org)
  • frequencies
  • Our method uses classical diffusion approximations to model temporal fluctuations in the selection coefficients to find the expected distribution of mutation frequencies in the population. (genetics.org)
  • An early exchange in this debate was over the changes in the frequencies of a color polymorphism in a population of the scarlet tiger moth, Callimorpha (Panaxia) dominula . (genetics.org)
  • research
  • A research on population genetic structure of Malay sub-ethnic groups published in 2011 revealed that Kelantanese Malays formed a separate independent clade, suggesting that Kelantanese Malay had an ancestry that is more divergent than any other Malay sub-ethnic groups. (wikipedia.org)