founder effect

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found·er ef·fect

an unusually high frequency of a gene in a particular population derived from a small set of unrepresentative ancestors.
Farlex Partner Medical Dictionary © Farlex 2012

founder effect

n.
A random difference in allele frequencies of a population founded by a small group of organisms relative to the allele frequencies in the original population.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

founder effect

the result of starting a new population with a low number of individuals (founders), so that their GENE POOL may not contain the same proportions of ALLELES for a particular LOCUS as in the original population. For example, instead of containing three alleles of the ABO BLOOD GROUP locus, Australian aborigines contain no B alleles and thus no Group B or Group AB individuals are produced, a situation probably caused by a ‘founder effect’. Such small founder populations are subject to RANDOM GENETIC DRIFT.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Beyond rare diseases, groups with founder effects hold lessons about common diseases and basic biology, said Alan Shuldiner, a professor of medicine at the University of Maryland and a genetics researcher for Regeneron Pharmaceuticals, who was not involved in the study.
The founder effect on genetic variability of experimental populations of mosquito fish were measured by the allozymes electrophoretic technique by Leberg (1992), who estimated the values of proportion of polymorphic loci, number of alleles per locus and heterozygosity.
"There's not a lot of actual history written down, but the belief is that the Ashkenazis derived from settlers who probably came into the Rhineland around the 9th or 10th century and formed this distinct endogamous group." The 14th-century founder effect was likely also the result of immigration, largely to Lithuania and the surrounding region.
Note also that CEO tenure, a control variable, was significant and negative (b = -.064, p < .05), suggesting a counterbalance to the founder effect. A post hoc test of the interaction between founder status and board tenure failed to disclose statistically significant results.
In populations with founder effects, such as the Ashkenazi Jewish population, testing is far cheaper as it can be targeted to a few mutations.
The latter include migration, founder effect, neutral in situ differentiation, non-random mating and population size fluctuation (Cavalli-Sforza et al.
Multiple reports of SCA 1 in Italy, South Africa, northern Japan and Russia, reflect the varied prevalence and suggest multiple founder effects. Frequency of SCA1 from South Africa (40%) and Italy (41%) represents the highest frequencies reported from any country (7, 8).
Loss of genetic diversity, both in wild and captive populations, raises concerns about the potential impact of inbreeding, genetic bottlenecks, and founder effects. Wildlife preserves and zoos have attempted to address this problem by creating studbooks, biological databases, which can be used to determine family lineages and relatedness among individuals of the same species.
A central theme of the book is evaluation of the extent to which novel forms on islands are generated predominantly via founder effects alone (including population bottlenecks, loss of genetic variation, and subsequent random drift and genome reorganization) versus adaptation via directional selection for new phenotypes in new insular environments (see especially Chapter 8 for an overview of alternatives).
Founder effects and sex ratio in the gynodioecious Thymus vulgaris L.
This would lead to an increased number of descendants with specific mutations in some of their genes, even though robust evidence for such founder effects, especially in rare conditions, are yet to be found.