Chromosomal Differences between European and North American Atlantic salmon Discovered by Linkage Mapping and Supported by Fluorescence in situ Hybridization Analysis

BACKGROUND:Geographical isolation has generated a distinct difference between Atlantic salmon of European and North American Atlantic origin. The European Atlantic salmon generally has 29 pairs of chromosomes and 74 chromosome arms whereas it has been reported that the North American Atlantic salmon has 27 chromosome pairs and an NF of 72. In order to predict the major chromosomal rearrangements causing these differences, we constructed a dense linkage map for Atlantic salmon of North American origin and compared it with the well-developed map for European Atlantic salmon.RESULTS:The presented male and female genetic maps for the North American subspecies of Atlantic salmon, contains 3,662 SNPs located on 27 linkage groups. The total lengths of the female and male linkage maps were 2,153cM and 968cM respectively, with males characteristically showing recombination only at the telomeres. We compared these maps with recently published SNP maps from European Atlantic salmon, and predicted three chromosomal reorganization events that we then tested using fluorescence in situ hybridization (FISH) analysis. The proposed rearrangements, which define the differences in the karyotypes of the North American Atlantic salmon relative to the European Atlantic salmon, include the translocation of the p arm of ssa01 to ssa23 and polymorphic fusions: ssa26 with ssa28, and ssa08 with ssa29.CONCLUSIONS:This study identified major chromosomal differences between European and North American Atlantic salmon. However, while gross structural differences were significant, the order of genetic markers at the fine-resolution scale was remarkably conserved. This is a good indication that information from the International Cooperation to Sequence the Atlantic salmon Genome, which is sequencing a European Atlantic salmon, can be transferred to Atlantic salmon from North America

Protest, voting and political change : the effects of NGOs on politics in developing democracies

This dissertation examines the political effects of NGOs in developing democracies. There is a large and contradictory literature on whether, how, and why NGOs affect politics. Some argue that NGOs are an essential component of a strong civil society necessary for democratic consolidation. Others argue that NGOs are co- opted by the existing hierarchy of political elites, and politicians claim credit for the services they provide, damaging democratic accountability. I argue that NGOs have systematic effects on politics in two realms: participation and voting behavior. First, I agree with the conventional wisdom that NGOs tend to boost participation of all kinds. However, I argue that - particularly in weakly democratic settings - NGOs are likely to encourage unconventional means of participation such as demonstrations and protest in addition to more conventional forms such as voting. This is a strong challenge to the common assumption in the literature that NGOs are the bulwark of moderate civil society. Second, I argue that the effects of NGOs on voting behavior are conditional on the size of the jurisdiction in question. Existing work predicts starkly contradictory political effects: Some claim NGOs should help incumbents by providing services for which politicians can claim credit, while others claim they should hurt incumbents by facilitating opposition. I argue that both these effects are possible, but in different contexts. In areas with very small populations, the associational effects of NGOs (their ability to bring people together, air common grievances, and build trust to help solve collective action problems) are much stronger, making it more likely that NGO activity will strengthen opposition politics. In larger population areas, however, the effects of increases in association are relatively much smaller. And, in the more impersonal setting of larger cities, credit-claiming for NGO services is easier. Thus, NGOs in larger cities are likely to help incumbents, rather than help the opposition. I test my argument and competing hypotheses from the literature using a new approach: an analysis of an original sub-national dataset comparing municipalities in Bolivia. The dataset includes measures of NGO activity, election returns, and protest, as well as a number of controls, for two time periods, 1999 and 200

Phenotype and genotype data used in L. saxatilis GWAS

4066 SNP loci from 477 individuals identified using ddRAD, with minimum 70% genotyping rate, and no SNPs out of HWE. Phenotype file with aligned x and y coordinates, relative warps, partial warps, and centroid size

FATIGUE DAMAGE: REPEATED LOADING ENABLES CRABS TO OPEN LARGER BIVALVES

Volume: 171Start Page: 538End Page: 54

Latitudinal clines in body size, but not in thermal tolerance or heat-shock cognate 70 (HSC70), in the highly-dispersing intertidal gastropod Littorina keenae (Gastropoda: Littorinidae)

Natural populations of widely-distributed animals often exhibit clinal variation in phenotypic traits or in allele frequencies of a particular gene over their geographical range. A planktotrophic intertidal snail, Littorina keenae is broadly distributed along the north-eastern Pacific coast through a large latitudinal range (24°50´N-43°18´N). We tested for latitudinal clines in two complex phenotypic traits - thermal tolerance and body size - and one single locus trait ¨C heat shock cognate 70 (HSC70) - in L. keenae along almost its entire geographical range. We found only weak evidence for a latitudinal cline in the thermal tolerance and no evidence for a cline in allele frequencies at HSC70. However, as predicted by Bergmann's rule, we detected a strong latitudinal cline that accounted for 60% of the variance in body size (R2 = 0.598; P < 0.001). In contrast, body size did not significantly affect thermal tolerance. HSC70 showed no genetic differentiation among the populations, supporting our previous mitochondrial gene-based estimate of high gene flow during this snail's free-swimming larval stage. Given that L. keenae experiences panmixia along its species range, the observed size cline may be partially or entirely caused by a phenotypically plastic response to local thermal environments rather than by genetic divergence in body size among populations in response to locally optimizing natural selection

Data from: Genomic divergence between Spanish Littorina saxatilis ecotypes unravels limited admixture and extensive parallelism associated with population history

The rough periwinkle, Littorina saxatilis, is a model system for studying parallel ecological speciation in microparapatry. Phenotypically parallel wave-adapted and crab-adapted ecotypes that hybridize within the middle shore are replicated along the northwestern coast of Spain, and have likely arisen from two separate glacial refugia. We tested whether greater geographic separation corresponding to reduced opportunity for contemporary or historical gene flow between parallel ecotypes resulted in less parallel genomic divergence. We sequenced double-digested restriction-associated DNA (ddRAD) libraries from individual snails from upper, mid, and low intertidal levels of three separate sites colonized from two separate refugia. FDIST analysis of 4256 SNP markers identified 34.4% sharing of divergent loci between two geographically-close sites, however, these sites each shared only 9.9-15.1% of their divergent loci with a third more-distant site. STRUCTURE analysis revealed that genotypes from only three of 166 phenotypically intermediate mid-shore individuals appeared to result from recent hybridization suggesting that hybrids cannot be reliably identified using shell traits. Hierarchical AMOVA indicated that the primary source of genomic differentiation was geographic separation, but also revealed greater similarity of the same ecotype across the two geographically-close sites than previously estimated with dominant markers. These results from a model system for ecological speciation suggest that genomic parallelism is affected by the opportunity for historical or contemporary gene flow between populations

A genome scan for selection signatures comparing farmed Atlantic salmon with two wild populations: Testing colocalization among outlier markers, candidate genes, and quantitative trait loci for production traits

publishedVersio

Periodic invasions during El Niño events by the predatory lined shore crab (Pachygrapsus crassipes): forecasted effects of its establishment on direct-developing indigenous prey species (Littorina spp.)

Coevolutionary arms races between shelled gastropods and their predators are more escalated near the equator. Therefore, temperate gastropods are predicted to be maladapted to highly specialized tropical shell-crushing crabs. The northern geographical limit of the lined shore crab (Pachygrapsus crassipes J.W. Randall, 1840) does not usually overlap with the southern limit of the Sitka periwinkle (Littorina sitkana Philippi, 1846), which lacks a pelagic larval stage. Large El Niño events increased the winter abundance and poleward transport of P. crassipes larvae from California (USA) in the Davidson Current. Temporary intertidal crab populations that included females with eggs were observed 1–4 years later, >1000 km north of its usual geographical range. Laboratory experiments showed that L. sitkana did not have a size refuge from adult P. crassipes. Moreover, consumption rates of adult L. sitkana by P. crassipes were 10-fold higher than those published for indigenous purple shore crabs (Hemigrapsus nudus (Dana, 1851)) with similar claw sizes. Additionally, the upper intertidal limit of invading P. crassipes was higher than that of H. nudus. Consequently, the invasion of P. crassipes reduced the width of L. sitkana‘s spatial refuge from predation. The permanent presence of this subtropical predator could reduce the intertidal distribution of this temperate gastropod, thereby causing contraction of its southern range limit.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Tethering data November 2013 crab ecotype

Tethering results for November 2013 at high and mid intertidal levels at Cabo Silleiro with 4 mm crab ecotype and 9 mm crab ecotype. 2nd sheet has codes for shell fragments