Mesobuthus

Abstract: There has been very little undisputed evidence for recombination in animal mitochondrial DNA (mtDNA) provided so far. Previous unpublished results suggestive of mtDNA recombination in the scorpion family Buthidae, together with cytological evidence for a unique mechanism of mitochondrial fusion in that family, prompted us to investigate this group in more details. First, we sequenced the complete mtDNA genome of Mesobuthus gibbosus, and chose two genes opposing each other (16S and coxI). We then sequenced 150 individuals from the natural populations of four species of Buthidae (Old World genera Buthus and Mesobuthus). We observed strong evidence for widespread recombination through highly significant negative correlations between linkage disequilibrium and physical distance in three out of four species. The evidence is further confirmed when using five other tests for recombination and by the presence of a high amount of homoplasy in phylogenetic trees.

Abstract: Sequence data derived from two mitochondrial markers, 16S rRNA and COI genes, were used to infer the evolutionary history of 47 insular and mainland populations covering most of the distributional range of the northeastern Mediterranean scorpion species Mesobuthus gibbosus. Based on the estimated divergence times of Mesobuthus lineages, the temporal frame of the genus differentiation in the northeastern Mediterranean region is placed in middle Miocene (15 million years ago). The biogeographic affinities of M. gibbosus populations point towards a mainly vicariant pattern of differentiation of the species which is consistent with the geological events that transformed the Aegean region during the period from 12 to 5 million years ago. M. gibbosus is an old northeastern Mediterranean species that has retained valuable bits of genetic information, reflecting some of the oldest vicariant events that have occurred in the area. Most importantly, the history witnessed by M. gibbosus has not been obscured by more recent palaeoevents of the region. Therefore, the case of M. gibbosus is in favour of a taxon-oriented 'perception' of the natural history of a given area.

Abstract: The first molecular phylogeny is presented for four species of the scorpion genus Meso- buthus, based on DNA sequences of three gene fragments (two mitochondrial and one nuclear protein coding gene, ;1 kb). The inferred phylogeny based on a pooled maximum likelihood analysis revealed a clear deep splitting between the ''western clade'' consisting of M. gibbosus and M. cyprius (Greece/ Anatolia, Cyprus) and the ''eastern clade'' consisting of M. eupeus and M. caucasicus (Anatolia/Central Asia). The species M. caucasicus (recently placed in the genus Olivierus Farzanpay 1987) groups mon- ophyletically within Mesobuthus; thus, the genus Olivierus is synonymized here with Mesobuthus. Se- quences of M. eupeus and M. caucasicus sampled mainly from Kazakhstan and Uzbekistan are highly structured, indicating the possible existence of multiple species.

Abstract: Scorpions of the genus Mesobuthus represent a useful terrestrial model system for studying molecular evolution. They are distributed on several Aegean islands and the adjacent mainland, they are believed to have low rates of dispersal, and evolutionary divergence dates of taxa are available based on biogeographic events that separated islands from each other and the mainland. Here, we present data on polymorphism and synonymous (Ks) and nonsynonymous (Ka) substitution rates for nine nuclear protein-coding genes of two east Mediterranean scorpion species, Mesobuthus gibbosus and M. cyprius (Buthidae). Levels of polymorphism tend to be lower in populations from islands (mean nucleotide diversity π = 0.0071 ± 0.0028) than in mainland populations (mean π = 0.0201 ± 0.0085). By using linear regression of genetic divergence versus isolation time, we estimate Ks to be 3.17 ± 1.54 per (site × 109 years), and Ka to be 0.39 ± 0.94 per (site × 109 years). These estimates for both Ks and Ka are considerably ...