Distribution and habitat use by sympatric dormice species in two Natura 2000 sites in central Macedonia, Greece

There has been little research on the distribution and ecology of the four dormouse species occurring in Greece; the Edible Dormouse (Glis glis), Forest Dormouse (Dryomys nitedula), Hazel dormouse (Muscardinus avellanarius) and Mouse-tailed Dormouse (Myomimus roachi). As a result, the latter three species are listed as data deficient (DD) in the National Red Data Book. Recently, the government has tried to address this knowledge gap, funding dormouse surveys within the Natura 2000 network. In this context, we used a combination of nest-tubes (n=442) and track-tunnels (n=238) to study dormouse distribution and habitat use across 37 sites representing different habitat types (with varying levels of grazing) of two mountainous N2K sites (GR1270001, GR1270005) in central Macedonia. We detected G. glis at 28 sites, D. nitedula at 32 sites, and M. avellanarius at seven sites. Positive identification of the different species was twice as likely in track-tunnels (unbaited; metal sheets covered in soot) than nest-tubes. We estimated relative abundance across sites using Royle-Nichols occupancy models, except for M. avellanarius due to data limitations. For all species, we examined habitat use using MaxEnt ecological-niche models. Our findings show that D. nitedula has the widest distribution, occurring even in sparse forests and maqui with moderate or high livestock grazing intensity. G. glis is common, but restricted to medium-high elevation forests. M. avellanarius appears to have a discontinuous distribution. If this study is representative of its status across the country, that species requires conservation efforts

Quantitative variation of LINE-1 sequences in five species and three subspecies of the subgenus Mus and in five Robertsonian races of Mus musculus domesticus

The quantitative variation of a conserved region of the LINE-1 ORF2 sequence was determined in eight species and subspecies of the subgenus Mus (M. m. domesticus, M. m. musculus, M. m. castaneus, M. spicilegus, M. spretus, M. cervicolor, M. cookii, M. caroli) and five Robertsonian races of M. m. domesticus. No differences in LINE-1 ORF2 content were found between all acrocentric or Robertsonian chromosome races, whereas the quantitative variation of the LINE-1 ORF2 sequences detected among the eight taxa partly matches with the clades into which the subgenus is divided. An accumulation of LINE-1 ORF2 elements likely occurred during the evolution of the subgenus. Within the Asiatic clade, M. cervicolor, cookii, and caroli show a low quantity of LINE-1 sequences, also detected within the Palearctic clade in M. m. castaneus and M. spretus, representing perhaps the ancestral condition within the subgenus. On the other hand, M. m. domesticus, M. m. musculus and M. spicilegus showed a high content of LINE-1 ORF2 sequences. Comparison between the chromosomal hybridization pattern of M. m. domesticus, which possesses the highest content, and M. spicilegus did not show any difference in the LINE-1 ORF2 distribution, suggesting that the quantitative variation of this sequence family did not involve chromosome restructuring or a preferential chromosome accumulation, during the evolution of M. m. domesticus

Morphometrics and genetics highlight the complex history of Eastern Mediterranean spiny mice

Spiny mice of the Acomys cahirinus group display a complex geographical structure in the Eastern Mediterranean area, as shown by previous genetic and chromosomal studies. To better elucidate the evolutionary relationships between insular populations from Crete and Cyprus and continental populations from North Africa and Cilicia in Turkey, genetic and morphometric variations were investigated, based on mitochondrial D-loop sequences, and the size and shape of the first upper molar. The Cypriot and the Cilician populations show idiosyncratic divergence in molar size and shape, while Cretan populations present a geographical structure with at least three differentiated subpopulations, as shown by congruent distributions of haplogroups, Robertsonian fusions and morphometric variation. A complex history of multiple introductions is probably responsible for this structure, and insular isolation coupled with habitat shift should have further promoted a pronounced and rapid morphological evolution in molar size and shape on Crete and Cyprus

Trusts. A Comparative Study.

International audienceA selective sweep is the result of strong positive selection driving newly occurring or standing genetic variants to fixation, and can dramatically alter the pattern and distribution of allelic diversity in a population. Population-level sequencing data have enabled discoveries of selective sweeps associated with genes involved in recent adaptations in many species. In contrast, much debate but little evidence addresses whether "selfish" genes are capable of fixation-thereby leaving signatures identical to classical selective sweeps-despite being neutral or deleterious to organismal fitness. We previously described R2d2, a large copy-number variant that causes nonrandom segregation of mouse Chromosome 2 in females due to meiotic drive. Here we show population-genetic data consistent with a selfish sweep driven by alleles of R2d2 with high copy number (R2d2(HC)) in natural populations. We replicate this finding in multiple closed breeding populations from six outbred backgrounds segregating for R2d2 alleles. We find that R2d2(HC) rapidly increases in frequency, and in most cases becomes fixed in significantly fewer generations than can be explained by genetic drift. R2d2(HC) is also associated with significantly reduced litter sizes in heterozygous mothers, making it a true selfish allele. Our data provide direct evidence of populations actively undergoing selfish sweeps, and demonstrate that meiotic drive can rapidly alter the genomic landscape in favor of mutations with neutral or even negative effects on overall Darwinian fitness. Further study will reveal the incidence of selfish sweeps, and will elucidate the relative contributions of selfish genes, adaptation and genetic drift to evolution