This monograph covers many speciation mechanisms, including founder speciation, mainly from a theoretical population genetic perspective. Gavrilets confirms the objections of Barton, Charlesworth, and others to founder speciation by evolving through an adaptive valley, but he shows other mechanisms that make founder populations more likely to speciate.
Giddings, Luther V. Kaneshiro, and Wyatt W. Anderson, eds. Genetics, speciation and the founder principle. New York: Oxford Univ. This book contains chapters on the theory of founder effect speciation, natural examples, and genetic studies. An interview with Hampton Carson chapter 1 and a historical perspective by William Provine chapter 2 are valuable general introductions to this model of speciation and how it was developed.
Templeton, Alan R. The reality and importance of founder speciation in evolution. BioEssays This is the most recent review of this area. The three major theories of founder speciation are summarized, showing that none of them are based on adaptive peak shifts. A detailed statistical analysis of the empirical literature shows that the predictions and assumptions of founder effect speciation are strongly supported.
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Rotimi, Ph. Featured Content. Introduction to Genomics. UC Berkeley. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneck. Reduced genetic variation means that the population may not be able to adapt to new selection pressures, such as climatic change or a shift in available resources, because the genetic variation that selection would act on may have already drifted out of the population.
Northern elephant seals have reduced genetic variation probably because of a population bottleneck humans inflicted on them in the s. The effective founder population of Quebec was only 2, After twelve to sixteen generations, with an eighty-fold growth but minimal gene dilution from intermarriage, Quebec has what geneticists call optimal linkage disequilibrium genetic sharing. Founder effects can also occur naturally as competing genetic lines die out. This means that an effective founder population consists only of those whose genetic print is identifiable in subsequent populations.
Because in sexual reproduction, genetic recombination ensures that with each generation only half the genetic material of a parent is represented in the offspring, some genetic lines may die out entirely, even though there are numerous progeny. A recent study [2] concluded that of the people migrating across the Bering land bridge at the close of the ice age, only 70 left their genetic print in modern descendants, a minute effective founder population— which is easily misread as though implying that only 70 people crossed to North America.
The misinterpretations of " Mitochondrial Eve " are a case in point: it may be hard to explain that a "mitochondrial Eve" was not the only woman of her time. In humans, founder effects can arise from cultural isolation, and inevitably, endogamy.
For example, the Amish populations in the United States, which have grown from a very few founders, have not recruited newcomers, and tend to marry within the community, exhibit founder effects. Though still rare absolutely, phenomena such as polydactyly extra fingers and toes, a symptom of Ellis-van Creveld syndrome are more common in Amish communities than in the US population at large.
There is also the presence of high cases of fumarase deficiency among the 10, members of the Fundamentalist Church of Jesus Christ of Latter Day Saints community, a breakaway sect which practices both endogamy and polygamy, where it is estimated 75 to 80 percent of the community are blood relatives of just two men - founders John Y. Barlow and Joseph Smith Jessop.
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