The spatial subdivision of species often plays a pivotal role in speciation. Across their entire range, species are rarely panmictic and crucial consequences of spatial subdivision are (1) random genetic drift including historical factors, (2) uniform selection, and (3) divergent selection. Each of these consequences may result in geographic variation and eventually reproductive isolation, but ...

the isolation-by-distance theory states that the genetic differentiation between individuals raised by increasing geographic distance. therefore, this study tested this hypothesis for garra rufa , a freshwater fish species of iranian inland waters, from six rivers located at the different distances in tirgis basin. for this purpose, eight variable microsatellite loci were applied to identify ge...

Most diploid species arise from single-species ancestors. Hybrid origins of new species are uncommon (except among polyploids) and are documented infrequently in animals. Examples of natural hybridization leading to speciation in mammals are exceedingly rare. Here, we show a Caribbean species of bat (Artibeus schwartzi) has a nuclear genome derived from two nonsister but congeneric species (A. ...

Two recent studies provide convincing evidence that speciation without geographic isolation--sympatric speciation--has occurred within isolated island habitats, but we remain ignorant of how frequent the process really is.

Environments vary across space and time, and behavioural divergence among populations is commonplace. Differences in behaviour may represent genetic divergence or phenotypic plasticity, and arise from abiotic or biotic factors. In turn, such differences in behaviour may promote reproductive isolation and speciation, and they may also influence how traits such as mating displays relate to fitnes...

The recent recognition of provisional Neurospora phylogenetic species (PS) 1-3 gave us the opportunity to compare genetic isolation, which underlies phylogenetic species recognition (PSR), with reproductive isolation as criteria for recognizing new species. This investigation involved first finding new individuals of PS 1-3 from a search of the Perkins culture collection, then assessing genetic...

Geographically limited dispersal can shape genetic population structure and result in a correlation between genetic and geographic distance, commonly called isolation-by-distance. Despite the prevalence of isolation-by-distance in nature, to date few studies have empirically demonstrated the processes that generate this pattern, largely because few populations have direct measures of individual...

PREMISE OF THE STUDY Mountain plants are among the species most vulnerable to global warming, because of their isolation, narrow geographic distribution, and limited geographic range shifts. Stochastic and selective processes can act on the genome, modulating genetic structure and diversity. Fragmentation and historical processes also have a great influence on current genetic patterns, but the ...