Victor Fet

Evidence for recombination in scorpion mitochondrial DNA (Scorpiones: Buthidae)

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 Previous unpublished results suggestive of mtDNA recombination in the scorpion family Buthidae, together with cytological evidence for a unique mechanism of mitochondrial fusion in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.

Non-LTR retrotransposons in fungi

Non-long terminal repeat (non-LTR) retrotransposons have contributed to shaping the structure and function of genomes. Fungi have small genomes, usually with limited amounts of repetitive DNA. In silico approach has been used to survey the non-LTR elements in 57 fungal genomes. More than 100 novel non-LTR retrotransposons were found, which belonged to five diverse clades. The present survey identified two novel clades of fungal non-LTR retrotransposons. The copy number of non-LTR retroelements varied widely. Some of the studied species contained a single copy of non-LTR retrotransposon, whereas others possessed a great number of non-LTR retrotransposon copies per genome. Although evolutionary relationships of most elements are congruent with phylogeny of host species, a new case of possible horizontal transfer was found between Eurotiomycetes and Sordariomycetes.

CR1 clade of non-LTR retrotransposons from Maculinea butterflies (Lepidoptera: Lycaenidae): evidence for recent horizontal transmission

BackgroundNon-long terminal repeat (non-LTR) retrotransposons are mobile genetic elements that propagate themselves by reverse transcription of an RNA intermediate. Non-LTR retrotransposons are known to evolve mainly via vertical transmission and random loss. Horizontal transmission is believed to be a very rare event in non-LTR retrotransposons. Our knowledge of distribution and diversity of insect non-LTR retrotransposons is limited to a few species – mainly model organisms such as dipteran genera Drosophila, Anopheles, and Aedes. However, diversity of non-LTR retroelements in arthropods seems to be much richer. The present study extends the analysis of non-LTR retroelements to CR1 clade from four butterfly species of genus Maculinea (Lepidoptera: Lycaenidae).The lycaenid genus Maculinea, the object of interest for evolutionary biologists and also a model group for European biodiversity studies, possesses a unique, specialized myrmecophilous lifestyle at larval stage. Their caterpillars, after three weeks of phytophagous life on specific food plants drop to the ground where they are adopted to the ant nest by Myrmica foraging workers.ResultsWe found that the genome of Maculinea butterflies contains multiple CR1 lineages of non-LTR retrotransposons, including those from MacCR1A, MacCR1B and T1Q families. A comparative analysis of RT nucleotide sequences demonstrated an extremely high similarity among elements both in interspecific and intraspecific comparisons. CR1A-like elements were found only in family Lycaenidae. In contrast, MacCR1B lineage clones were extremely similar to CR1B non-LTR retrotransposons from Bombycidae moths: silkworm Bombyx mori and Oberthueria caeca.ConclusionThe degree of coding sequence similarity of the studied elements, their discontinuous distribution, and results of divergence-versus-age analysis make it highly unlikely that these sequences diverged at the same time as their host taxa. The only reasonable alternative explanation is horizontal transfer. In addition, phylogenetic markers for population analysis of Maculinea could be developed based on the described non-LTR retrotransposons.

Euscorpius balearicus Caporiacco, 1950, stat. nov. (Scorpiones: Euscorpiidae): molecular (allozymes and mtDNA) and morphological evidence for an endemic Balearic Islands species

Abstract The geographic variation of the circum-Mediterranean scorpion species Euscorpius carpathicus (L.) was traditionally analysed using morphological characters such as trichobothrial patterns, which resulted in the recognition of 23 subspecies; however, the biological reality of these subspecies remains unclear. Here, we focus on populations from the western Mediterranean and provide new molecular evidence that those from the island of Mallorca (Balearic Islands, Spain) represent a highly divergent lineage separate from E. carpathicusfrom the mainland of France (Vaucluse) and Italy (Liguria and Piemonte). This divergence is evidenced by morphological analysis. Moreover, allozyme and mtDNA divergences (about 10%) agree with our hypothesis that the Balearic island populations became isolated from the mainland about 5 Ma BP since the refilling of the Mediterranean Basin and have to be considered autochthonous. This hypothesis is additionally supported by the comparison of the genetic differentiation between artificially transplanted island populations and mainland populations in the congeneric species E. flavicaudis(de Geer). The phylogenetic species concept (PSC) is applied to elevate the subspecies E. carpathicus balearicus Caporiacco, 1950 to species rank. A lectotype is designated for this species.

THE FIRST DNA PHYLOGENY OF FOUR SPECIES OF MESOBUTHUS (SCORPIONES, BUTHIDAE) FROM EURASIA

Abstract The first molecular phylogeny is presented for four species of the scorpion genus Mesobuthus, 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 monophyletically within Mesobuthus; thus, the genus Olivierus is synonymized here with Mesobuthus. Sequences of M. eupeus and M. caucasicus sampled mainly from Kazakhstan and Uzbekistan are highly structured, indicating the possible existence of multiple species.

Phylogeography of co-distributed dune scorpions identifies the Amu Darya River as a long-standing component of Central Asian biogeography

Abstract Although only distantly related, Anomalobuthus and Liobuthus are monotypic and sympatric scorpion genera with psammophilic phenotypes well-suited to the dune communities of the Karakum and Kyzylkum deserts of Central Asia. We predicted that this unique combination of phenotypic convergence and sympatry should have resulted in shared phylogeographic histories. We tested this hypothesis by using mitochondrial DNA data and molecular dating techniques to reconstruct the matrilineal genealogies of A. rickmersi and L. kessleri. We also developed current and late-glacial species distribution models and landscape interpolations of genetic distances to assess the influence of historical barriers and Pleistocene climates on the phylogeography of each species. Both genera exhibited signals of restricted gene flow across the Amu Darya River, supporting our prediction of mutual histories. Levels of initial genetic differentiation within each genus date to the Late Miocene to late Pliocene. Distribution models indicate that suitable habitat may have fragmented during the Pleistocene, generally in an east-west orientation. Although the observed genetic differentiation at the Amu Darya River could be a coincidental product of lineage sorting, the fact that both species display this pattern suggests that the river has been an important biogeographic element in the development of Central Asian biotas.

AN EXTREMELY LOW GENETIC DIVERGENCE ACROSS THE RANGE OF EUSCORPIUS ITALICUS (SCORPIONES, EUSCORPIIDAE)

Abstract Little or no genetic divergence is detected using mitochondrial 16S rDNA sequence comparisons across the entire geographic range of the scorpion Euscorpius italicus (Herbst 1800) from Switzerland, Italy, Slovenia, Greece and Turkey. This is consistent with known absence of patterns of allozymes and morphological variation. Euscorpius italicus is found almost exclusively in human habitations. Its sister species, E. naupliensis, exhibits much higher genetic diversity within southern Greece. We suggest that the natural populations of the thermophilic E. italicus underwent a bottleneck during the glaciations, and that its modern range could be a result of dispersal with humans.

Fauna and Zoogeography of Scorpions (Arachnida: Scorpiones) in Bulgaria

The fauna and zoogeography of scorpions in Bulgaria have not been well researched. At least four species are recorded currently for this country: the Balkan–Anatolian Mesobuthus gibbosus (Buthidae), known only from Pirin Mts., and several taxa of the genus Euscorpius Thorell (Euscorpiidae). The Balkan species E. hadzii inhabits the southwest of Bulgaria, and an undetermined species of the Balkan–Anatolian ‘‘Euscorpius mingrelicus’’ complex is known only from Pirin Mts. Remaining Bulgarian populations of Euscorpius, widely ranging from north to south (mainly in the mountain areas, up to 1850 m a.s.l.), belong to ‘‘Euscorpius carpathicus’’ complex. Their true taxonomic identity is not yet known, but these populations are not homogeneous. A clearly separated cluster of Rhodope populations could represent a different taxon from the Stara Planina ( = Balkan) ones (mainly known from the Western Stara Planina) and those from the southwest of Bulgaria. Taxonomic affinities of Bulgarian scorpion taxa are discussed, as well as their geographic and altitudinal distribution

FIRST RECORD FOR THE GENUS MESOBUTHUS VACHON, 1950 IN ISRAEL: MESOBUTHUS NIGROCINCTUS (EHRENBERG, 1828), N. COMB.(SCORPIONES: BUTHIDAE) FROM MT. HERMON

The first record for the genus Mesobuthus in Israel is herein reported based onadult specimens of Mesobuthus nigrocinctus (Ehrenberg, 1828), n. comb.(Scorpiones, Buthidae) from Mt. Hermon, the southernmost ridge of the Anti-Lebanon range. This species was originally described from a juvenile specimen from Lebanon, and for a long time was considered a synonym of M. gibbosus (Brulle, 1832). The species is redescribed, illustrated, and compared to M. gibbosus, its closest relative. Some comments on the fauna of Mt.Hermon are included.

Divergent non-LTR retrotransposon lineages from the genomes of scorpions (Arachnida: Scorpiones)

We screened across the taxonomic diversity of order Scorpiones (22 species belonging to 21 genera and 10 families) for the presence of seven different clades of non-LTR retrotransposons in their genomes using PCR with newly designed clade-specific consensus-degenerate hybrid oligonucleotide primers. Scorpion genomes were found to contain four known non-LTR retrotransposon clades: R1, I, Jockey, and CR1. In total, 35 fragments of reverse transcriptase genes of new elements from 22 scorpion species were obtained and analyzed for three clades, Jockey, I, and CR1. Phylogenies of different clades of elements were built using amino acid sequences inferred from 33 non-LTR retrotransposon clones. Distinct evolutionary lineages, with several major groups of the non-LTR retroelements were identified, showing significant variation. Four lineages were revealed in Jockey clade. The phylogeny of I clade showed strong support for the monophyletic origin of such group of elements in scorpions. Three separate lineages can be distingiushed in the phylogenetic tree of CR1 clade. The large fraction of the isolated elements appeared to be defective.