Phylogeographical studies are typically based on haplotype data, occasionally on nuclear markers such as microsatellites, but rarely combine both. This is unfortunate because the use of markers with contrasting modes of inheritance and rates of evolution might provide a more accurate and comprehensive understanding of a species' history. Here we present a detailed study of the phylogeography of the greater horseshoe bat, Rhinolophus ferrumequinum, using 1098 bp of the mitochondrial ND2 gene from 45 localities from across its Palaearctic range to infer population history. In addition, we re-analysed a large microsatellite data set available for this species and compared the results of both markers to infer population relationships and the historical processes influencing them. We show that mtDNA, the most popular marker in phylogeography studies, yielded a misleading result, and would have led us to conclude erroneously that a single expansion had taken place in Europe. Only by combining the mitochondrial and microsatellite data sets are we able to reconstruct the species' history and show two colonization events in Europe, one before the Last Glacial Maximum (LGM) and one after it. Combining markers also revealed the importance of Asia Minor as an ancient refugium for this species and a source population for the expansion of the greater horseshoe bat into Europe before the LGM.
The distribution of genetic variability across a species' range can provide valuable insights into colonization history. To assess the relative importance of European and Asian refugia in shaping current levels of genetic variation in the greater horseshoe bats, we applied a microsatellite-based approach to data collected from 56 localities ranging from the UK to Japan. A decline in allelic richness from west Asia to the UK and analyses of F(ST) both imply a northwestward colonization across Europe. However, sharp discontinuities in gene frequencies within Europe and between the Balkans and west Asia (Syria/Russia) are consistent with suture zones following expansion from multiple refugia, and a lack of recent gene flow from Asia Minor. Together, these results suggest European populations originated from west Asia in the ancient past, and experienced a more recent range expansion since the Last Glacial Maximum. Current populations in central Europe appear to originate from the Balkans and those from west Europe from either Iberia and/or Italy. Comparisons of R(ST )and F(ST) suggest that stepwise mutation has contributed to differentiation between island and continental populations (France/UK and China/Japan) and also among distant samples. However, pairwise R(ST) values between distant populations appear to be unreliable, probably due to size homoplasy. Our findings also highlight two priorities for conservation. First, stronger genetic subdivision within the UK than across 4000 km of continental Eurasia is most likely the result of population fragmentation and highlights the need to maintain gene flow in this species. Second, deep splits within China and between Europe and China are indicative of cryptic taxonomic divisions which need further investigation.
Here, we present a study of the Pipistrellus pipistrellus species complex, a highly diversified bat group with a radiation centre in the Mediterranean biodiversity hotspot. The study sample comprised 583 animals from 118 localities representatively covering the bats' range in the western Palearctic. We used fast-evolving markers (the mitochondrial D-loop sequence and 11 nuclear microsatellites) to describe the phylogeography, demography and population structure of this model taxon and address details of its diversification. The overall pattern within this group includes a mosaic of phylogenetically basal, often morphologically distant, relatively small and mostly allopatric demes in the Mediterranean Basin, as well as two sympatric sibling species in the large continental part of the range. The southern populations exhibit constant size, whereas northern populations show a demographic trend of growth associated with range expansion during the Pleistocene climate oscillations. There is evidence of isolation by distance and female philopatry in P. pipistrellus sensu stricto. Although the northern populations are reproductively isolated, we detected introgression events among several Mediterranean lineages. This pattern implies incomplete establishment of reproductive isolating mechanisms in these populations as well as the existence of a past reinforcement stage in the continental siblings. The occurrence of reticulations in the radiation centre among morphologically and ecologically derived relict demes suggests that adaptive unequal gene exchange within hybridizing populations could play a role in speciation and adaptive radiation within this group.
Significance
Retroviruses copy their RNA genome into complementary DNA, which is then inserted into the host chromosomal DNA as an obligatory part of their life cycle. Such integrated viral sequences, called proviruses, are passed to the infected cell progeny on cellular division. If germline cells are targeted, the proviruses become vertically inherited as other host genes and are called endogenous retroviruses. Deltaretroviruses, which include important human and veterinary pathogens (HTLV-1 and BLV), are the last retroviral genus for which endogenous forms were not known. We have identified a case of endogenous Deltaretrovirus, which entered the genome of long-fingered bat ancestors more than 20 million years ago. This finding opens the way for elucidating the deep evolutionary history of deltaretroviruses.
International audienceChalcogenide glasses from Ge-Sb-Se ternary system with different antimony content were fabricated and basic physico-chemical properties (chemical composition, thermal characteristics, density) were evaluated considering the glassy network connectivity. Optical properties of the glasses were heavily studied employing transmission spectroscopy, prism coupling technique, and particularly spectroscopic ellipsometry covering broad spectral range (0.3-20 μm). Refractive indices data show very good agreement between ellipsometry and prism coupling techniques in near-infrared range. Moreover, the reliability of infrared spectroscopic ellipsometry was demonstrated for precise determination of refractive index of chalcogenide glasses in near- as well as middle-infrared spectral regions
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