Bumblebee family lineage survival is enhanced in high-quality landscapes.

Insect pollinators such as bumblebees (Bombus spp.) are in global decline. A major cause of this decline is habitat loss due to agricultural intensification.

Temporal and spatial instability in neutral and adaptive (MHC) genetic variation in marginal salmon populations.

The role of marginal populations for the long-term maintenance of species' genetic diversity and evolutionary potential is particularly timely in view of the range shifts caused by climate change. The Centre-Periphery hypothesis predicts that marginal populations should bear reduced genetic diversity and have low evolutionary potential. We analysed temporal stability at neutral microsatellite and adaptive MHC genetic variation over five decades in four marginal Atlantic salmon populations located at the southern limit of the species' distribution with a complicated demographic history, which includes stocking with foreign and native salmon for at least 2 decades.

Effects of habitat composition and landscape structure on worker foraging distances of five bumble bee species.

Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations.

NFAT5 genes are part of the osmotic regulatory system in Atlantic salmon (Salmo salar).

The anadromous Atlantic salmon utilizes both fresh and salt water (FW and SW) habitats during its life cycle. The parr-smolt transformation (PST) is an important developmental transition from a FW adapted juvenile parr to a SW adapted smolt. Physiological changes in osmoregulatory tissues, particularly the gill, are key in maintaining effective ion regulation during PST.

Functional divergence of type 2 deiodinase paralogs in the Atlantic salmon.

Thyroid hormone (TH) is an ancestral signal linked to seasonal life history transitions throughout vertebrates. TH action depends upon tissue-localized regulation of levels of active TH (triiodothyronine, T3), through spatiotemporal expression of thyroid hormone deiodinase (dio) genes. We investigated the dio gene family in juvenile Atlantic salmon (Salmo salar) parr, which prepare for seaward migration in the spring (smoltification) through TH-dependent changes in physiology.

Fine-scale spatial genetic structure of common and declining bumble bees across an agricultural landscape.

Land-use changes have threatened populations of many insect pollinators, including bumble bees. Patterns of dispersal and gene flow are key determinants of species' ability to respond to land-use change, but have been little investigated at a fine scale (<10 km) in bumble bees. Using microsatellite markers, we determined the fine-scale spatial genetic structure of populations of four common Bombus species (B.

Extensive local gene duplication and functional divergence among paralogs in Atlantic salmon.

Many organisms can generate alternative phenotypes from the same genome, enabling individuals to exploit diverse and variable environments. A prevailing hypothesis is that such adaptation has been favored by gene duplication events, which generate redundant genomic material that may evolve divergent functions. Vertebrate examples of recent whole-genome duplications are sparse although one example is the salmonids, which have undergone a whole-genome duplication event within the last 100 Myr.

Reproductive conflict in bumblebees and the evolution of worker policing.

Worker policing (mutual repression of reproduction) in the eusocial Hymenoptera represents a leading example of how coercion can facilitate cooperation. The occurrence of worker policing in "primitively" eusocial species with low mating frequencies, which lack relatedness differences conducive to policing, suggests that separate factors may underlie the origin and maintenance of worker policing. We tested this hypothesis by investigating conflict over male parentage in the primitively eusocial, monandrous bumblebee, Bombus terrestris.

Phylogenetic relationships in Pterodroma petrels are obscured by recent secondary contact and hybridization.

The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948. In this study we investigate the relationships between Round Island petrels and their closest relatives using evidence from mitochondrial DNA sequence data and ectoparasites.

Range expansion and hybridization in Round Island petrels (Pterodroma spp.): evidence from microsatellite genotypes.

Historical records suggest that the petrels of Round Island (near Mauritius, Indian Ocean) represent a recent, long-distance colonization by species originating from the Atlantic and Pacific Oceans. The majority of petrels on Round Island appear most similar to Pterodroma arminjoniana, a species whose only other breeding locality is Trindade Island in the South Atlantic. Using nine microsatellite loci, patterns of genetic differentiation in petrels from Round and Trindade Islands were analysed.

Genomic organization and evolution of the vomeronasal type 2 receptor-like (OlfC) gene clusters in Atlantic salmon, Salmo salar.

There are three major multigene superfamilies of olfactory receptors (OR, V1R, and V2R) in mammals. The ORs are expressed in the main olfactory organ, whereas the V1Rs and V2Rs are located in the vomeronasal organ. Fish only possess one olfactory organ in each nasal cavity, the olfactory rosette; therefore, it has been proposed that their V2R-like genes be classified as olfactory C family G protein-coupled receptors (OlfC).

Sites of evolutionary divergence differ between olfactory and gustatory receptors of Drosophila.

olfactory (ORs) and gustatory (GRs) receptors are evolutionarily unrelated to vertebrate ORs or nematode chemosensory receptors. Insect ORs display a reverse membrane topology compared with conventional G-protein-coupled receptors, suggesting that the mammalian scheme of chemosensory signal transduction cannot directly apply to insects. Experimental studies of GR membrane topology are lacking.

Cross-species characterisation of polymorphic microsatellite loci in the giant otter (Pteronura brasiliensis).

Nineteen microsatellite loci developed for the Eurasian otter (Lutra lutra) and 15 loci developed for the North American river otter (Lontra canadensis) were tested for ease of amplification and degree of polymorphism on a set of 20 giant otter (Pteronura brasiliensis) faecal samples from the Bolivian Amazon basin. Nineteen loci amplified consistently well, with polymorphisms ranging from two to nine alleles and observed heterozygosity ranging from 0.15 to 0.

Drosophila chemoreceptor gene evolution: selection, specialization and genome size.

Chemoperception plays a key role in adaptation and speciation in animals, and the senses of olfaction and gustation are mediated by gene families which show large variation in repertoire size among species. In Drosophila, there are around 60 loci of each type and it is thought that ecological specialization influences repertoire size, with increased pseudogenization of loci. Here, we analyse the size of the gustatory and olfactory repertoires among the genomes of 12 species of Drosophila.

Evolution of a complex locus: exon gain, loss and divergence at the Gr39a locus in Drosophila.

Background: Gene families typically evolve by gene duplication followed by the adoption of new or altered gene functions. A different way to evolve new but related functions is alternative splicing of existing exons of a complex gene. The chemosensory gene families of animals are characterised by numerous loci of related function.

Evolution of genes and genomes on the Drosophila phylogeny.

Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution.

Rare and fleeting: an example of interspecific recombination in animal mitochondrial DNA.

Recombination is thought to occur only rarely in animal mitochondrial DNA (mtDNA). However, detection of mtDNA recombination requires that cells become heteroplasmic through mutation, intramolecular recombination or 'leakage' of paternal mtDNA. Interspecific hybridization increases the probability of detecting mtDNA recombinants due to higher levels of sequence divergence and potentially higher levels of paternal leakage.

Genetic analysis of male reproductive success in relation to density in the zebrafish, Danio rerio.

Background: We used behavioural and genetic data to investigate the effects of density on male reproductive success in the zebrafish, Danio rerio. Based on previous measurements of aggression and courtship behaviour by territorial males, we predicted that they would sire more offspring than non-territorial males.

Results: Microsatellite analysis of paternity showed that at low densities territorial males had higher reproductive success than non-territorial males.

Differential gene expression and phenotypic plasticity in behavioural castes of the primitively eusocial wasp, Polistes canadensis.

Understanding how a single genome can produce a variety of different phenotypes is of fundamental importance in evolutionary and developmental biology. One of the most striking examples of phenotypic plasticity is the female caste system found in eusocial insects, where variation in reproductive (queens) and non-reproductive (workers) phenotypes results in a broad spectrum of caste types, ranging from behavioural through to morphological castes. Recent advances in genomic techniques allow novel comparisons on the nature of caste phenotypes to be made at the level of the genes in organisms for which there is little genome information, facilitating new approaches in studying social evolution and behaviour.

Isolation and characterisation of main olfactory and vomeronasal receptor gene families from the Atlantic salmon (Salmo salar).

The Atlantic salmon (Salmo salar) has been widely used as a model species in studies of olfactory signal transduction and processing. Here we report the isolation and characterisation of salmon olfactory receptor (SOR) and salmon vomeronasal receptor (SVR) partial sequences from Atlantic salmon. Six groups of SOR sequences (SORA-F) and three groups of SVR sequences (SVRA-C) were identified.

Differential gene expression in queen-worker caste determination in bumble-bees.

Investigating how differential gene expression underlies caste determination in the social Hymenoptera is central to understanding how variation in gene expression underlies adaptive phenotypic diversity. We investigated for the first time the association between differential gene expression and queen-worker caste determination in the bumble-bee Bombus terrestris. Using suppression subtractive hybridization we isolated 12 genes that were differentially expressed in queen- and worker-destined larvae.

Social parasitism by male-producing reproductive workers in a eusocial insect.

The evolution of extreme cooperation, as found in eusocial insects (those with a worker caste), is potentially undermined by selfish reproduction among group members. In some eusocial Hymenoptera (ants, bees and wasps), workers can produce male offspring from unfertilized eggs. Kin selection theory predicts levels of worker reproduction as a function of the relatedness structure of the workers' natal colony and the colony-level costs of worker reproduction.

Using nested clade analysis to assess the history of colonization and the persistence of populations of an Iberian Lizard.

The distribution of the lizard Lacerta schreiberi is likely to have been severely affected by the climatic cycles that have influenced the Iberian Peninsula. Information about the species ecology and Iberian physiogeography was used to generate specific hypotheses about episodes of colonization and subsequent population persistence. These hypotheses generated predictions about the distribution of genetic variation, which were tested using nested clade analysis (NCA) supplemented by analysis of molecular variance (amova).

DNA EVOLUTION AND COLONIZATION SEQUENCE OF ISLAND LIZARDS IN RELATION TO GEOLOGICAL HISTORY: MTDNA RFLP, CYTOCHROME B, CYTOCHROME OXIDASE, 12S RRNA SEQUENCE, AND NUCLEAR RAPD ANALYSIS.

A novel source of nuclear DNA information from random amplified polymorphisms (RAPD) and a wide-range mitochondrial DNA information (cytochrome b, cytochrome oxidase, and 12s rRNA sequence, RFLP from 4-base and 6-base recognition endonucleases) are used to reconstruct the population phylogeny of the western Canary Island lizard, Gallotia galloti, which, for geological reasons, has been subject to dispersal but not vicariance. Interpretation of DNA phylogenies in terms of colonization sequence indicates that G. galloti arose in Tenerife and dispersed westward in two independent pathways: north from north Tenerife to La Palma, and south from south Tenerife to Gomera to Hierro.