Balancing a cline by influx of migrants: a genetic transition in water frogs of eastern Greece.

Variation patterns of allozymes and of ND3 haplotypes of mitochondrial DNA reveal a zone of genetic transition among western Palearctic water frogs extending across northeastern Greece and European Turkey. At the western end of the zone, allozymes characteristic of Central European frogs known as Pelophylax ridibundus predominate, whereas at the eastern end, alleles characteristic of western Anatolian water frogs (P. cf.

RrS1-like sequences of water frogs from Central Europe and around the Aegean Sea: chromosomal organization, evolution, possible function.

RrS1-like sequences of water frogs (genus Pelophylax) display varied genomic organization, whereas the centromeric hybridization pattern reveals species-specific differences. Using fluorescent in situ hybridization, Pelophylax cf. bedriagae, Pelophylax kurtmuelleri, and Pelophylax ridibundus showed a hybridization signal at centromeres of chromosomes 1-5, but in P.

Phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs have been determined by geological processes and climate change in the Late Cenozoic.

AIM: Our aims were to assess the phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs and to estimate divergence times using different geological scenarios. We related divergence times to past geological events and discuss the relevance of our data for the systematics of eastern Mediterranean water frogs. LOCATION: The eastern Mediterranean region.

Evolution of serum albumin intron-1 is shaped by a 5' truncated non-long terminal repeat retrotransposon in western Palearctic water frogs (Neobatrachia).

A 5' truncated non-LTR CR1-like retrotransposon, named RanaCR1, was identified in the serum albumin intron-1 (SAI-1) of at least seven species of western Palearctic water frogs (WPWF). Based on sequence similarity of the carboxy-terminal region (CTR) of ORF2 and/or the highly conserved 3' untranslated region (3' UTR), RanaCR1-like elements occur also in the genome of Xenopus tropicalis and Rana temporaria. Unlike other CR1 elements, RanaCR1 contains a CA microsatellite in its 3' UTR.

Comparative analysis of mitochondrial genomes in Bombina (Anura; Bombinatoridae).

The complete mitochondrial genomes of two basal anurans, Bombina bombina and B. variegata (Anura; Bombinatoridae), were sequenced. The gene order of their mitochondrial DNA (mtDNA) is identical to that of canonical vertebrate mtDNA.

Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes.

The fire-bellied toads Bombina bombina and Bombina variegata, interbreed in a long, narrow zone maintained by a balance between selection and dispersal. Hybridization takes place between local, genetically differentiated groups. To quantify divergence between these groups and reconstruct their history and demography, we analysed nucleotide variation at the mitochondrial cytochrome b gene (1096 bp) in 364 individuals from 156 sites representing the entire range of both species.

Gametogenesis of intergroup hybrids of hemiclonal frogs.

European water frog hybrids Rana esculenta (R. ridibundaxR. lessonae) reproduce hemiclonally, by hybridogenesis: in the germ line they exclude the genome of one parental species and produce haploid gametes with an unrecombined genome of the other parental species.

Hagfish intestinal antimicrobial peptides are ancient cathelicidins.

Three potent broad-spectrum antimicrobial peptides (HFIAP-1, -2, and -3) isolated from intestinal tissues of Myxine glutinosa (Atlantic hagfish) are identified as ancient members of the cathelicidin family of antimicrobial peptides, hitherto known only from mammals. In situ hybridization reveals that HFIAPs are produced in nests of myeloid cells within the loose connective tissue of the gut wall, a tissue reminiscent of both gut-associated lymphoid tissue (GALT) and vertebrate spleen. We suggest that this tissue organization provides local defense of the hagfish gastrointestinal tract via innate immunity and possibly served as the architectural plan upon which the adaptive immune system evolved.

GEOLOGICALLY DATED SEA BARRIERS CALIBRATE A PROTEIN CLOCK FOR AEGEAN WATER FROGS.

Reliable estimates of phylogenetic relationships and divergence times are a crucial requirement for many evolutionary studies, but are usually difficult because fossils are scarce and their interpretation is often uncertain. Frogs are fresh water animals that generally are unable to cross salt water barriers (their skin is readily permeable to both salt and water). The geologically determined ages of salt water barriers that isolate related frog populations thus provide an independent measure of the minimum date of genetic divergence between pairs of such populations.

GYNOGENETIC REPRODUCTION IN HYBRID MOLE SALAMANDERS (GENUS AMBYSTOMA).

Ambystoma platineum, a unisexual clonal triploid taxon of mole salamander, originated by hybridization between the Mendelian species A. jeffersonianum and A. laterale.