title: Horizontal gene transfer, dispersal and haloarchaeal speciation.
abstract: The Halobacteria are a well-studied archaeal class and numerous investigations are showing how their diversity is distributed amongst genomes and geographic locations. Evidence indicates that recombination between species continuously facilitates the arrival of new genes, and within species, it is frequent enough to spread acquired genes amongst all individuals in the population. To create permanent independent diversity and generate new species, barriers to recombination are probably required. The data support an interpretation that rates of evolution (e.g., horizontal gene transfer and mutation) are faster at creating geographically localized variation than dispersal and invasion are at homogenizing genetic differences between locations. Therefore, we suggest that recurrent episodes of dispersal followed by variable periods of endemism break the homogenizing forces of intrapopulation recombination and that this process might be the principal stimulus leading to divergence and speciation in Halobacteria.
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA. thane@uconn.edu.
authors.forename: R Thane
authors.initials: RT
authors.lastname: Papke
authors.affiliation: Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain. pcv@us.es.
authors.forename: Paulina
authors.initials: P
authors.lastname: Corral
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Ram-Mohan
authors.affiliation: Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain. rrh@us.es.
authors.forename: Rafael R
authors.initials: RR
authors.lastname: de la Haba
authors.affiliation: Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain. sanpor@us.es.
authors.forename: Cristina
authors.initials: C
authors.lastname: Sánchez-Porro
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA. andrea.makkay@uconn.edu.
authors.forename: Andrea
authors.initials: A
authors.lastname: Makkay
authors.affiliation: Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain. ventosa@us.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ventosa
keywords: Haloarchaea; biogeography; homologous recombination; horizontal gene transfer; population genetics; speciation