Parallel habitat acclimatization is realized by the expression of different genes in two closely related salamander species (genus Salamandra).

The utilization of similar habitats by different species provides an ideal opportunity to identify genes underlying adaptation and acclimatization. Here, we analysed the gene expression of two closely related salamander species: Salamandra salamandra in Central Europe and Salamandra infraimmaculata in the Near East. These species inhabit similar habitat types: 'temporary ponds' and 'permanent streams' during larval development. We developed two species-specific gene expression microarrays, each targeting over 12 000 transcripts, including an overlapping subset of 8331 orthologues. Gene expression was examined for systematic differences between temporary ponds and permanent streams in larvae from both salamander species to establish gene sets and functions associated with these two habitat types. Only 20 orthologues were associated with a habitat in both species, but these orthologues did not show parallel expression patterns across species more than expected by chance. Functional annotation of a set of 106 genes with the highest effect size for a habitat suggested four putative gene function categories associated with a habitat in both species: cell proliferation, neural development, oxygen responses and muscle capacity. Among these high effect size genes was a single orthologue (14-3-3 protein zeta/YWHAZ) that was downregulated in temporary ponds in both species. The emergence of four gene function categories combined with a lack of parallel expression of orthologues (except 14-3-3 protein zeta) suggests that parallel habitat adaptation or acclimatization by larvae from S. salamandra and S. infraimmaculata to temporary ponds and permanent streams is mainly realized by different genes with a converging functionality.

No signs of inbreeding despite long-term isolation and habitat fragmentation in the critically endangered Montseny brook newt (Calotriton arnoldi).

Endemic species with restricted geographic ranges potentially suffer the highest risk of extinction. If these species are further fragmented into genetically isolated subpopulations, the risk of extinction is elevated. Habitat fragmentation is generally considered to have negative effects on species survival, despite some evidence for neutral or even positive effects. Typically, non-negative effects are ignored by conservation biology. The Montseny brook newt (Calotriton arnoldi) has one of the smallest distribution ranges of any European amphibian (8 km2) and is considered critically endangered by the International Union for Conservation of Nature. Here we apply molecular markers to analyze its population structure and find that habitat fragmentation owing to a natural barrier has resulted in strong genetic division of populations into two sectors, with no detectable migration between sites. Although effective population size estimates suggest low values for all populations, we found low levels of inbreeding and relatedness between individuals within populations. Moreover, C. arnoldi displays similar levels of genetic diversity to its sister species Calotriton asper, from which it separated around 1.5 million years ago and which has a much larger distribution range. Our extensive study shows that natural habitat fragmentation does not result in negative genetic effects, such as the loss of genetic diversity and inbreeding on an evolutionary timescale. We hypothesize that species in such conditions may evolve strategies (for example, special mating preferences) to mitigate the effects of small population sizes. However, it should be stressed that the influence of natural habitat fragmentation on an evolutionary timescale should not be conflated with anthropogenic habitat loss or degradation when considering conservation strategies.

Eight new tetranucleotide microsatellite loci for the agile frog (Rana dalmatina).

We describe eight new polymorphic tetranucleotide microsatellite loci isolated from the agile frog (Rana dalmatina). In 25 individuals from the Nature Reserve Lüneburger Heide (Lower Saxony, Germany), the number of alleles per locus ranged from four to nine and average observed heterozygosities from 69.1% to 80.7%. No evidence for linkage disequilibrium was found and none of the loci showed significant deviation from Hardy-Weinberg expectations. These microsatellite DNA markers are suitable tools for addressing population genetics issues in this endangered species.

Mitochondrial sequence analysis of Salamandra taxa suggests old splits of major lineages and postglacial recolonizations of central Europe from distinct source populations of Salamandra salamandra.

Representatives of the genus Salamandra occur in Europe, Northern Africa and the Near East. Many local variants are known but species and subspecies status of these is still a matter of dispute. We have analysed samples from locations covering the whole expansion range of Salamandra by sequence analysis of mitochondrial D-loop regions. In addition, we have calibrated the rate of divergence of the D-loop on the basis of geologically dated splits of the closely related genus Euproctus. Phylogenetic analysis of the sequences suggests that six major monophyletic groups exist (S. salamandra, S. algira, S. infraimmaculata, S. corsica, S. atra and S. lanzai) which have split between 5 and 13 million years ago (Ma). We find that each of the Salamandra species occupies a distinct geographical area, with the exception of S. salamandra. This species occurs all over Europe from Spain to Greece, suggesting that it was the only species that has recolonized Central Europe after the last glaciation. The occurrence of specific east and west European haplotypes, as well as allozyme alleles in the S. salamandra populations suggests that this recolonization has started from at least two source populations, possibly originating in the Iberian peninsula and the Balkans. Two subpopulations of S. salamandra were found that are genetically very distinct from the other populations. One lives in northern Spain (S. s. bernardezi) and one in southern Italy (S. s. gigliolii). Surprisingly, the mitochondrial lineages of these subpopulations group closer together than the remainder S. salamandra lineages. We suggest that these populations are remnants of a large homogeneous population that had colonized Central Europe in a previous interglacial period, approximately 500 000 years ago. Animals from these populations were apparently not successful in later recolonizations. Still, they have maintained their separate genetic identity in their areas, although they are not separated by geographical barriers from very closely related neighbouring populations.