Linkage mapping reveals sex-dimorphic map distances in a passerine bird

Linkage maps are lacking for many highly influential model organisms in evolutionary research, including all passerine birds. Consequently, their full potential as research models is severely hampered. Here, we provide a partial linkage map and give novel estimates of sex-specific recombination rates in a passerine bird, the great reed warbler (Acrocephalus arundinaceus). Linkage analysis of genotypic data at 51 autosomal microsatellites and seven markers on the Z-chromosome (one of the sex chromosomes) from an extended pedigree resulted in 12 linkage groups with 2–8 loci. A striking feature of the map was the pronounced sex-dimorphism: males had a substantially lower recombination rate than females, which resulted in a suppressed autosomal map in males (sum of linkage groups: 110.2cM) compared to females (237.2cM; female/male map ratio: 2.15). The sex-specific recombination rates will facilitate the building of a denser linkage map and cast light on hypotheses about sex-specific recombination rates

Evolutionary relationships of southern ocean Octopodidae (Cephalopoda:Octopoda) and a new diagnosis of <i>Pareledone</i>.

The phylogenetic relationships of eight species of incirrate octopodid from western Antarctica were investigated using molecular sequence data from the mitochondrial 16s ribosomal RNA gene. The genus Pareledone, which is endemic to the Antarctic, was found to be polyphyletic. On the basis of this and previous morphological studies, it is suggested that species that are morphologically similar to Pareledone polymorpha should be removed from the genus. This simplifies the diagnosis of Pareledone: a new diagnosis is given. The subfamilies Eledoninae and Graneledoninae were also found to be polyphyletic. The applicability of using the presence of an ink sac as a taxonomic character to define the subfamilies is discussed. Loss of an ink sac is almost certainly an adaptation to depth and use of this character has produced an artificial classification with no evolutionary significance. As the other two subfamilies, Octopodinae and Bathypolypodinae, are also separated by this character, it is probable that all the subfamilies of the Octopodidae are polyphyletic. The use of subfamilies should therefore be discontinued until our understanding of the evolution of the family Octopodidae increases

Development of a real-time PCR assay for detection of Mytilus species specific alleles: application to a sampling survey in Scotland

Shellfish aquaculture is a growing industry in Scotland, dominated by the production of the mussel Mytilus edulis, the native species. Recently the discovery of Mytilus galloprovincialis and Mytilus trossulus together with M. edulis and all 3 hybrids in cultivation in some Scottish sea lochs led to questions regarding the distribution of mussel species in Scotland. The establishment of an extensive sampling survey, involving the collection of mussels at 34 intertidal sites and 10 marinas around Scotland, motivated the development of a high-throughput method for identification of Mytilus alleles from samples. Three Taqman®–MGB probes and one set of primers were designed, based on the previously described Me 15/16 primers targeting the adhesive protein gene sequence, and samples were screened for the presence of M. edulis, M. galloprovincialis and M. trossulus alleles using real-time PCR. Mytilus edulis alleles were identified in samples from all 44 sites. Mytilus galloprovincialis alleles were found together with M. edulis alleles extensively in northern parts of the west and east coasts. Mytilus trossulus alleles were identified in samples from 6 sites in the west and south-west of Scotland. Because M. trossulus is generally undesirable in cultivation and therefore preventing the geographical spread of this species across Scotland is considered beneficial by the shellfish aquaculture industry, these 6 samples were further analysed for genotype frequencies using conventional PCR. Although distribution of the non-native species M. galloprovincialis and M. trossulus have proven to be more widespread than previously thought, there is no evidence from our study of either M. trossulus or M. galloprovincialis acting as an invasive species in Scotland. The real-time PCR method developed in this study has proven to be a rapid and effective tool for the identification of M. edulis, M. galloprovincialis and M. trossulus alleles from samples and should prove useful in future surveys, ecological or aquaculture management related studies in both unispecific and mixed species areas of these species

Comparison of the cost of short flights in a nectarivorous and a non-nectarivorous bird

Although most birds are accustomed to making short flights, particularly during foraging, the flight patterns during these short periods of activity differ between species. Nectarivorous birds, in particular, often spend time hovering, while non-nectarivorous birds do not. The cost of short flights is likely therefore to differ between nectarivorous and non-nectarivorous birds because of the different energetic contributions of different flight types to the behaviour. The 13C-labelled bicarbonate technique was used to measure the energy cost of short flights in the nectarivorous Palestine sunbird Nectarinia osea (mean mass 6.17±0.16 g, N=8) and the non-nectarivorous starling Sturnus vulgaris (mean mass 70.11±1.11 g, N=9). The technique was initially calibrated in five individuals for each species at temperatures ranging from 1 to 35°C, by comparing the isotope elimination rate to the metabolic rate measured simultaneously by indirect calorimetry. The cost for short intermittent flight was then measured by encouraging birds to fly between two perches at either end of a narrow corridor (perch distance for sunbirds, 6 m; for starlings, 5 m), and measuring the amount of isotope eliminated during the flight. The isotope elimination rate was interpolated onto the calibration equation to predict flight cost, as a direct calibration could not be performed during flight. Mean energy expenditure during flight was 1.64±0.32 W in sunbirds, while in starlings the flight costs averaged 20.6±0.78 W. Energy cost of flight relative to basal metabolic rate was substantially greater in the starling than the sunbird. Phylogenetic analysis of different modes of flight in these and additional species suggests that differences in flight behaviour may cause these elevated costs in slow flying non-nectarivores such as starlings, compared to birds that are more prone to short intermittent flights like the sunbirds.

Local differentiation in the presence of gene flow in the citril finch Serinus citrinella

It is well known theoretically that gene flow can impede genetic differentiation between populations. In this study, we show that in a highly mobile bird species, where dispersal is well documented, there is a strong genetic and morphological differentiation over a very short geographical scale (less than 5 km). Allocation tests revealed that birds caught in one area were assigned genetically to the same area with a very high probability, in spite of current gene flow. Populations were also morphologically differentiated. The results suggest that the relationship between gene flow and differentiation can be rather complicated and non-intuitive

Fine scale population structure of bottlenose dolphins (Tursiops truncatus) off Galician waters, NW Spain

Bottlenose dolphins are known to have high dispersal capabilities that could lead to genetic connectivity. However, local resident populations are found worldwide as happens in southern Galicia (NW Spain). The aim of this research is to explore whether population substructure and habitat segregation do exist within the Galician bottlenose dolphin community. In the present study, samples from 43 bottlenose dolphins stranded or by-caught in Galicia between 1994 and 2008 were genotyped at 10 microsatellite loci and sequenced at the highly variable mitochondrial control region. In addition, variability of stable isotope ratios (δ13C and δ15N) was assessed for 43 dolphins (5 calves, 38 juveniles and adults) stranded or by-caught in Galicia between 1998 and 2007. Genetic results highlighted the existence of two populations in the area and dolphins from southern Galicia were assigned to a single genetic group. Seven dolphins were classified as possible migrants between putative populations as their genetic makeup did not correspond with their geographical stranding location. Values of δ13C and δ15N were significantly different between the two populations, suggesting resource specialization and partitioning. Dolphins from southern Galicia (inhabiting coastal inlets) showed more variation in their diet, higher trophic levels and greater δ13C compared to animals from northern Galicia (present in more open waters). The existence of fine scale population substructure should be considered in the future designation of Special Areas of Conservation (SACs) for the species as required by the European Habitats Directive

Enchytraeid worm abundance and delta 13C cholesterol data from Sourhope field experiment site, Scotland, 2000 [NERC Soil Biodiversity Programme]

This dataset comprises enchytraeid worm abundance and Delta 13C values from enchytraeid cholesterol. The data were collected as a component of the NERC Soil Biodiversity Programme, consisting of a one year study of the diversity and activity of Enchytraeid worms, small relatives of the earthworm. These worms are very common in upland soils and often outweigh all other fauna, including sheep. The project focused on investigating the importance of Enchytraeid species, or group diversity, in maintaining soil carbon cycling. The NERC Soil Biodiversity Thematic Programme was established in 1999 and was centred upon the intensive study of a large field experiment located at the Macaulay Land Use Research Institute (now the James Hutton Institute)'s farm at Sourhope in the Scottish Borders. During this time, the site was monitored to assess changes in aboveground biomass production (productivity), species composition and relative abundance (diversity)