founder effect: a standalone construct

Ernst Mayr introduced the idea as the "founder principle" in his 1942 book Systematics and the Origin of Species, describing how a new population started by a few colonising individuals carries only a small, non-random sample of the genetic variation present in the larger source population. Because that founding sample, and not natural selection, sets the starting allele frequencies (the relative proportions of the alternative forms of a gene), rare variants can be lost while others become common purely by chance. Alan Templeton (1980) and Barton and Charlesworth (1984) later formalised how such founding events interact with genetic drift and selection, and debated whether a founder event can, on its own, trigger the origin of a new species. The founder effect is the special case of genetic drift that occurs at the moment a population is established, and it is invoked to explain unusual gene frequencies and the elevated rates of certain inherited disorders in populations descended from small groups of settlers. A separate, non-biological use of the phrase in organisational studies, describing the lasting imprint of a company's founders, is not treated as a construct here.[1][2][3]

Unit

A named evolutionary process that shifts allele frequencies at the founding of a population

Recovery means

Not applicable

Measured by

Detected by comparing genetic diversity and allele frequencies in a derived population against its source population, and modelled through genetic drift and coalescent treatments of the founding event