Gene genealogies in a metapopulation

Citation
J. Wakeley et N. Aliacar, Gene genealogies in a metapopulation, GENETICS, 159(2), 2001, pp. 893-905
Citations number
66
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology,"Molecular Biology & Genetics
Journal title
GENETICS
ISSN journal
0016-6731 → ACNP
Volume
159
Issue
2
Year of publication
2001
Pages
893 - 905
Database
ISI
SICI code
0016-6731(200110)159:2<893:GGIAM>2.0.ZU;2-I
Abstract
A simple genealogical process is found for samples from a metapopulation, w hich is a population that is subdivided into a large number of demes, each of which is subject to extinction and recolonization and receives migrants from other demes. As in the migration-only models studied previously, the g enealogy of any sample includes two phases: a brief sample-size adjustment followed by a coalescent process that dominates the history. This result wi ll hold for metapopulations that are composed of a large number of domes. I t is robust to the details of population structure, as long as the number o f possible source domes of migrants and colonists for each deme is large. A nalytic predictions about levels of genetic variation are possible, and res ults for average numbers of pairwise differences within and between domes a re given. Further analysis of the expected number of segregating sites in a sample from a single dome illustrates some previously known differences be tween migration and extinction/recolonization. The ancestral process is als o amenable to computer simulation. Simulation results show that migration a nd extinction/recolonization have very different effects on the site-freque ncy distribution in a sample from a single deme. Migration can cause a U-sh aped site-frequency distribution, which is qualitatively similar to the pat tern reported recently for positive selection. Extinction and recolonizatio n, in contrast, can produce a mode in the site-frequency distribution at in termediate frequencies, even in a sample from a single dome.