Molecular evolution of the Asian francolins (Francolinus, Galliformes): a modern reappraisal of a classic study in speciation.

We investigated the evolution of the Asian francolins, five little known species in the genus Francolinus (Phasianidae). Evolutionary affinities of two of these species, F. gularis (swamp francolin) and F. pondicerianus (grey francolin), has long remained unclear. In contrast, the other three species, F. pintadeanus (Chinese francolin), F. pictus (painted francolin) and F. francolinus (black francolin) have been cast among the "spotted francolins" on a morphological and ecological basis. Previous molecular DNA investigations including Asian francolins mostly relied upon partial gene sequencing of one specimen per species (no more than three species and with the exclusion of F. pictus). Therefore, fundamental questions do persist. What relationship exists among the spotted and the other Asian francolins? What is the geographic origin of the black francolin, the species with the largest distribution range? How did the geological history influence the diversification of francolins across Asia? We sequenced the entire Control Region of the mitochondrial DNA in 228 samples of all five Asian francolin species, which were collected in 16 countries (from East Europe to East Asia). We constructed a molecular phylogeny according to four different procedures. We showed the monophyly of each of the Asian francolins and the spotted group, while that of the entire Asian group was presumed according to a biogeographical model we proposed. The splitting of the genus Francolinus occurred ~17.4 Ma (95% HPD: 13.4-22.1) while the spotted francolins diverged ~10.5 Ma (7.0-14.9). We resolved the most recent common ancestor to painted and black francolin as being in the Indian sub-continent, thus suggesting a westwards adaptive radiation of the latter. In Pakistan, we identified F. f. asiae representatives in the Northern Areas and in the Sindh. The latter represents a relict population of Indian fauna within the Pakistani range of the Great Rann of Kachchh.

Molecular phylogeography of the asp viper Vipera aspis (Linnaeus, 1758) in Italy: evidence for introgressive hybridization and mitochondrial DNA capture.

Owing to its temperature dependence and low vagility, the asp viper (Vipera aspis) is an interesting model species to study the effects of Pleistocene climatic fluctuations on vertebrate genomes. We genotyped 102 specimens from the whole Italian distribution range at three mitochondrial DNA regions (2278 characters, total) and six microsatellite DNA loci (Short Tandem Repeats, STR). The molecular phylogeny was constructed according to Bayesian, Neighbour Joining, Maximum Parsimony and Maximum Likelihood procedures. All methods grouped individuals of the three morphological subspecies (V. a. aspis, V. a. francisciredi, V. a. hugyi) into five different haploclades. Specimens assigned to hugyi clustered in two highly differentiated clades, one being sister group to the complex comprising the second clade of hugyi (i.e., a paraphyletic status), plus two clades of francisciredi. The Bayesian clustering of the STR variability disclosed only two groups, the first including aspis and francisciredi, the second all hugyi. Introgressive hybridization and capture of francisciredi-like lineages in the hugyi mitochondrial genome were suggested to explain the discordance between mitochondrial and nuclear data. The phylogeographic pattern was compatible with population contractions in three glacial refuges. Plausibility of derived hypothesis was checked using coalescence simulations as post hoc tests. Long-term drift and serial founder effects, rather than selection, appeared the main factors affecting the genetic make-up of the Italian asp viper.

Cold microgradients elicit adaptive behavior in isotropically cooled, inert populations of Oxytricha bifaria (Ciliophora, Hypotrichida).

To complete our investigations on the oriented behavioral response of isotropically cooled, inert populations of Oxytricha bifaria to a warm thermal gradient, their physiological potentialities under cold microgradient conditions arising at 8.5 degrees C were studied. We monitored the behavior of the experimental populations, both at the level of the passing cold wave front, and afterwards when the thermal gradient stabilized, evaluating (i) their distribution in general, (ii) their relative centroids, (iii) the percentage of both backward creeping and immobile ciliates, and (iv) the numerical indices and rates of their creeping tracks. At the arrival of the cold wave front, the oxytrichas react immediately to the thermal stimulus, creep backwards at very high velocity along uninterrupted linear tracks, and thus move away from the cooling source. No specific behavioral response was ever observed in the static microgradient conditions. At 8.5 degrees C, despite their inertness, the ciliates are still able to behave adaptively, reacting immediately and orientatedly, once a directional factor (the cold-repelling thermal gradient) arises in an isotropic environment. This is similar to their behavior in the symmetric warm attracting thermal gradient.