Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

Wave energy and swimming performance shape coral reef fish assemblages

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance

Genetic diversity of a marine foundation species,Laminaria hyperborea(Gunnerus) Foslie, along the coast of Ireland

Worldwide, kelp populations are stressed by warming, increased storms and other anthropogenic disturbances. Marine population distributions are projected to retreat poleward with climate change if they cannot adapt to changing conditions, which would potentially lead to a regime shift in subtidal habitats. In Northern Europe,Laminaria hyperboreais a subtidal ecosystem engineer whose distribution has shifted over millennia, leaving predicted areas of high genetic diversity from the last glacial maximum (LGM) near its southern distribution limit in the Iberian Peninsula. In Ireland,L. hyperboreastructures communities by supporting diverse faunal assemblages and producing large quantities of organic carbon throughout the year. We investigated the genetic diversity of eight populations, ranging from the southern coast to the north-west of Ireland, using nine microsatellite loci. Diversity was found to be highest in Lough Hyne, a Special Area of Conservation (SAC), near the predicted climate refugium. We found evidence of isolation by distance, with high connectivity between populations that were geographically close, probably driven by short range dispersal ofL. hyperboreapropagules. Genetic diversity (measured as expected heterozygosity and allelic richness) was highest at Lough Hyne, and decreased northwards, as predicted from past range shifts. Expected heterozygosity was highest at Lough Hyne (0.706) and decreased northward, with the lowest value at Bridges of Ross (0.283). Based on these patterns, further fine-scale investigation into population diversity, dispersal and potential resilience in Irish kelp forests are necessary as warming and non-native species are observed more and more frequently.info:eu-repo/semantics/publishedVersio

Effects-based chemical category approach for prioritization of low affinity estrogenic chemicals

<div><p>Regulatory agencies are charged with addressing the endocrine disrupting potential of large numbers of chemicals for which there is often little or no data on which to make decisions. Prioritizing the chemicals of greatest concern for further screening for potential hazard to humans and wildlife is an initial step in the process. This paper presents the collection of <i>in vitro</i> data using assays optimized to detect low affinity estrogen receptor (ER) binding chemicals and the use of that data to build effects-based chemical categories following QSAR approaches and principles pioneered by Gilman Veith and colleagues for application to environmental regulatory challenges. Effects-based chemical categories were built using these QSAR principles focused on the types of chemicals in the specific regulatory domain of concern, i.e. non-steroidal industrial chemicals, and based upon a mechanistic hypothesis of how these non-steroidal chemicals of seemingly dissimilar structure to 17ß-estradiol (E2) could interact with the ER via two distinct binding types. Chemicals were also tested to solubility thereby minimizing false negatives and providing confidence in determination of chemicals as inactive. The high-quality data collected in this manner were used to build an ER expert system for chemical prioritization described in a companion article in this journal.</p></div

Root anchorage and its significance for submerged plants in shallow lakes.

Submerged plants in shallow lakes are subject to pulling forces arising from waves, currents and grazing birds. Such forces can cause anchorage failure (mainly dislodgement of the root system) or breaking failure of the stems. Both lead to loss of fitness but uprooting is more damaging because many perennial species can replace broken shoot systems. We investigated 12 abundant species (Ceratophyllum demersum, Chara sp., Eleogiton fluitans, Elodea canadensis, Myriophyllum spicatum, Najas marina, Potamogeton natans, P. obtusifolius, P. pectinatus, P. pusillus, Utricularia vulgaris and Zannichellia palustris) in 28 shallow lakes in the UK and the Netherlands. We measured the anchorage and breaking strengths of individual plants of different sizes. Anchorage strength depends on the cohesive strength of the sediment and the size of the root system. The undrained shear-strength of sediments in shallow lakes varied more than 50-fold, but all were substantially weaker than terrestrial soils. Anchorage strength was modelled using the product of sediment cohesive strength and four measures of root-system size. A transformation of plan-form area (raising it to the power 2/3) that represented the hemispherical surface area of the root ball was consistently the best predictor of anchorage strength. Breaking strength was a linear function of stem cross-sectional area in all species. Breaking stresses were comparable with those of marine algae and non-lignified terrestrial plants. The results were used, in combination with plant allometric relationships, to predict the fates of four of the species when challenged with the largest waves likely to be encountered in a 10-year period, and the even greater forces exerted by grazing birds. We show that sediment strength and plant size determine whether plants break or uproot. A careful balance between investment in anchorage and in breakage resistance is needed to survive in the fluctuating physical environment of lakes. Pulling forces experienced by aquatic plants are distinct from the mainly bending forces on more rigid land plants. We provide the first theoretical and quantitative framework for understanding their effects. Anchorage failure associated with the soft sediments of eutrophic lakes is likely to be a factor in the loss of macrophyte communities and an important factor in their restoration