FOUNDER EFFECT

=Founder Effect= If a small number of individuals emigrate or become isolated from their original population the colonising or founder population may not be a representative sample of the alleles in the parent population’s gene pool. Some alleles will be over-represented, some will be under-represented and some alleles will have been lost entirely. The newly founded population may be successful and eventually grow in numbers, even beyond that of the original ancestral population. However, the allele frequencies of these populations will still be markedly different. Some alleles would not have been present in the small group of founders and will therefore also be absent in their offspring. As a result some alleles will be missing in the newer population. [image:http://i.imgur.com/JUi6en4.jpg] Over time new alleles may be introduced to each population by mutations. However, the ancestral population is still likely to have greater genetic diversity because it will have had much more time for mutations to occur and produce new alleles. For instance, in humans, there is much greater genetic diversity (a larger variety of alleles) in some African populations. These are most likely the ancestral populations from which some individuals left and colonised other parts of the world. This is one of several lines of evidence that supports an African origin of ''Homo sapiens'' (modern humans). The small founding population is also impacted more severely by '''genetic drift''' and '''inbreeding'''. The underlying principles of founder effect / population bottlenecks are the same. A population is founded by, or reduced to a small number of individuals resulting in a loss of genetic diversity.