Evidence for strong genetic structure in European populations of the little owl Athene noctua

The little owl Athene noctua is a widespread species in Europe. This mainly sedentary owl experienced reduction in population sizes in some areas due to habitat loss and modification of the landscape. To assess the genetic structure of the populations of western and central Europe, we analysed 333 specimens from 15 geographical areas at 13 microsatellite loci. Statistical analyses and Bayesian clustering procedures detected two major genetically distinct clusters, the first distributed from Portugal to the Czech Republic and the second from the Balkans to Italy. The second cluster was further split into three groups, located in Italy, Sardinia and the Balkans. These groups match four previously‐described mtDNA haplogroups, and probably originated from the isolation of little owl populations in Sardinia and in three glacial refugia (Iberia, south Italy and Balkans) during the ice ages. High genetic admixture was recorded in central and northern Europe, probably as a consequence of the expansion from the refugia during interglacial. The main colonization route originated from the Iberian Peninsula towards central and northern Europe. Contact zones with colonization events from Italy and the Balkans were detected respectively in northern Italy and central Europe. Genetic indices show the existence of moderate levels of genetic variability throughout Europe, although evidence of recent evolutionary bottlenecks was found in some populations. Estimation of migration rates and approximate Bayesian computations highlighted the most likely phylogeographical scenario for the current distribution of little owl populations.     

The Mitochondrial Genome of Acropora tenuis (Cnidaria; Scleractinia) Contains a Large Group I Intron and a Candidate Control Region

The complete nucleotide sequence of the mitochondrial genome of the coral Acropora tenuis has been determined. The 18,338 bp A. tenuis mitochondrial genome contains the standard metazoan complement of 13 protein-coding and two rRNA genes, but only the same two tRNA genes (trnM and trnW) as are present in the mtDNA of the sea anemone, Metridium senile. The A. tenuis nad5 gene is interrupted by a large group I intron which contains ten protein-coding genes and rns; M. senile has an intron at the same position but this contains only two protein-coding genes. Despite the large distance (about 11.5 kb) between the 5?-exon and 3?-exon boundaries, the A. tenuis nad5 gene is functional, as we were able to RT-PCR across the predicted intron splice site using total RNA from A. tenuis. As in M. senile, all of the genes in the A. tenuis mt genome have the same orientation, but their organization is completely different in these two zoantharians: The only common gene boundaries are those at each end of the group I intron and between trnM and rnl. Finally, we provide evidence that the rns-cox3 intergenic region in A. tenuis may correspond to the mitochondrial control region of higher animals. This region contains repetitive elements, and has the potential to form secondary structures of the type characteristic of vertebrate D-loops. Comparisons between a wide range of Acropora species showed that a long hairpin predicted in rns-cox3 is phylogenetically conserved, and allowed the tentative identification of conserved sequence blocks.     

Metabolism of glucagon-like peptide-2 in pigs: role of dipeptidyl peptidase IV

Little is known about the metabolism of the intestinotropic factor glucagon-like peptide-2 (GLP-2); except that it is a substrate for dipeptidyl peptidase IV (DPP-IV) and that it appears to be eliminated by the kidneys. We, therefore, investigated GLP-2 metabolism in six multicatheterized pigs receiving intravenous GLP-2 infusions (2 pmol/kg/min) before and after administration of valine-pyrrolidide (300 mumol/kg; a well characterized DPP-IV inhibitor). Plasma samples were analyzed by radioimmunoassays allowing determination of intact, biologically active GLP-2 and the DPP-IV metabolite GLP-2 (3-33). During infusion of GLP-2 alone, 30.9+/-1.7% of the infused peptide was degraded to GLP-2 (3-33). After valine-pyrrolidide, there was no significant formation of the metabolite. Significant extraction of intact GLP-2 was observed across the kidneys, the extremities (represented by a leg), and the splanchnic bed, resulting in a metabolic clearance rate (MCR) of 6.80+/-0.47 ml/kg/min and a plasma half-life of 6.8+/-0.8 min. Hepatic extraction was not detected. Valine-pyrrolidide addition did not affect extraction ratios significantly, but decreased (p=0.003) MCR to 4.18+/-0.27 ml/kg/min and increased (p=0.052) plasma half-life to 9.9+/-0.8 min. The metabolite was eliminated with a half-life of 22.1+/-2.6 min and a clearance of 2.07+/-0.11 ml/kg/min. In conclusion, intact GLP-2 is eliminated in the peripheral tissues, the splanchnic bed and the kidneys, but not in the liver, by mechanisms unrelated to DPP-IV. However, DPP-IV is involved in the overall GLP-2 metabolism and seems to be the sole enzyme responsible for N-terminal degradation of GLP-2.     

From the Apennines to the Alps: colonization genetics of the naturally expanding Italian wolf (Canis lupus) population

Wolves in Italy strongly declined in the past and were confined south of the Alps since the turn of the last century, reduced in the 1970s to approximately 100 individuals surviving in two fragmented subpopulations in the central-southern Apennines. The Italian wolves are presently expanding in the Apennines, and started to recolonize the western Alps in Italy, France and Switzerland about 16 years ago. In this study, we used a population genetic approach to elucidate some aspects of the wolf recolonization process. DNA extracted from 3068 tissue and scat samples collected in the Apennines (the source populations) and in the Alps (the colony), were genotyped at 12 microsatellite loci aiming to assess (i) the strength of the bottleneck and founder effects during the onset of colonization; (ii) the rates of gene flow between source and colony; and (iii) the minimum number of colonizers that are needed to explain the genetic variability observed in the colony. We identified a total of 435 distinct wolf genotypes, which showed that wolves in the Alps: (i) have significantly lower genetic diversity (heterozygosity, allelic richness, number of private alleles) than wolves in the Apennines; (ii) are genetically distinct using pairwise F(ST) values, population assignment test and Bayesian clustering; (iii) are not in genetic equilibrium (significant bottleneck test). Spatial autocorrelations are significant among samples separated up to c. 230 km, roughly correspondent to the apparent gap in permanent wolf presence between the Alps and north Apennines. The estimated number of first-generation migrants indicates that migration has been unidirectional and male-biased, from the Apennines to the Alps, and that wolves in southern Italy did not contribute to the Alpine population. These results suggest that: (i) the Alps were colonized by a few long-range migrating wolves originating in the north Apennine subpopulation; (ii) during the colonization process there has been a moderate bottleneck; and (iii) gene flow between sources and colonies was moderate (corresponding to 1.25-2.50 wolves per generation), despite high potential for dispersal. Bottleneck simulations showed that a total of c. 8-16 effective founders are needed to explain the genetic diversity observed in the Alps. Levels of genetic diversity in the expanding Alpine wolf population, and the permanence of genetic structuring, will depend on the future rates of gene flow among distinct wolf subpopulation fragments.     

Long-distance dispersal of a wolf, <Emphasis Type="Italic">Canis lupus</Emphasis>, in northwestern Europe

Several mammal species have recolonized their historical ranges across Europe during the last decades. In November 2012, a wolf-looking canid was found dead in Thy National Park (56° 56′ N, 8° 25′ E) in Jutland, Denmark. DNA from this individual and nine German wolves were genotyped using a genome-wide panel of 22,163 canine single nucleotide polymorphism (SNP) markers and compared to existing profiles based on the same marker panel obtained from northeastern Polish (n?=?13) wolves, domestic dogs (n?=?13) and known wolf-dog hybrids (n?=?4). The Thy canid was confirmed to be a wolf from the German-western Polish population, approximately 800 km to the southeast. Access to the German reference database on DNA profiles based on 13 autosomal microsatellites of German wolves made it possible to pinpoint the exact pack origin of the Thy wolf in Saxony, Germany. This was the first documented observation of a wolf in Denmark in 200 years and another example of long-distance dispersal of a carnivore.