Mechanism of hybridization between bream Abramis brama and roach Rutilus rutilus in their native range.

Mechanisms of hybridization between bream Abramis brama and roach Rutilus rutilus were studied within the native range of the species in a lake in southern Finland. Through the genetic analysis of A. brama, R. rutilus and putative hybrids, hybridization is shown to have occurred between female A. brama and male R. rutilus. These results match with previous findings from introduced habitats, suggesting that mating between female A. brama and male R. rutilus is the predominant mechanism through which the two species hybridize.

HapStar: automated haplotype network layout and visualization.

Haplotype networks are commonly used for representing associations between sequences, yet there is currently no straightforward way to create optimal layouts. Automated optimal layouts are particularly useful not only because of the time-saving element but also because they avoid both human error and human-induced biases in the presentation of figures. HapStar directly uses the network connection output data generated from Arlequin (or a simple user-generated input file) and uses a force-directed algorithm to automatically lay out the network for easy visualization. In addition, this program is able to use the alternative connections generated by Arlequin to create a minimum spanning tree. HapStar provides a straightforward user-friendly interface, and publication-ready figures can be exported simply. HapStar is freely available (under a GPLv3 licence) for download for MacOSX, UNIX and Windows, at http://fo.am/hapstar.

European phylogeography of the common frog (Rana temporaria): routes of postglacial colonization into the British Isles, and evidence for an Irish glacial refugium.

We use phylogenetic techniques to investigate the postglacial re-population of Europe by the common frog and, in particular, the colonization of Ireland. Three main hypotheses have been proposed for the re-establishment of the Irish fauna after the last ice age: arrival across a late-glacial land bridge from Britain; expansion from a glacial refuge in the south of Ireland and, for some species, re-introduction by humans from Iberia. We examined the phylogeographic structure of 52 populations of the common frog (Rana temporaria) throughout Europe using 476-bp mitochondrial cytochrome b gene sequences. Our data replicate earlier studies in showing substantial sequence divergence (3%) between Eastern and Western European common frog haplotypes. However, we uncover a new evidence that these haplotypes co-exist in Spain, Switzerland and France, and infer an expansion of the eastern clade along the Mediterranean coastal corridor. All the British samples fall within the Western European clade, but the Irish data imply a different history. Genetically distinct haplotypes occur in populations from the south-west of Ireland. This local genetic differentiation may be a consequence of a local glacial refuge, possibly combined with natural colonization or introduction from Western Europe.