Environmental selection, rather than neutral processes, best explain regional patterns of diversity in a tropical rainforest fish.

To conserve the high functional and genetic variation in hotspots such as tropical rainforests, it is essential to understand the forces driving and maintaining biodiversity. We asked to what extent environmental gradients and terrain structure affect morphological and genomic variation across the wet tropical distribution of an Australian rainbowfish, Melanotaenia splendida splendida. We used an integrative riverscape genomics and morphometrics framework to assess the influence of these factors on both putative adaptive and non-adaptive spatial divergence. We found that neutral genetic population structure was largely explainable by restricted gene flow among drainages. However, environmental associations revealed that ecological variables had a similar power to explain overall genetic variation, and greater power to explain body shape variation, than the included neutral covariables. Hydrological and thermal variables were the strongest environmental predictors and were correlated with traits previously linked to heritable habitat-associated dimorphism in rainbowfishes. In addition, climate-associated genetic variation was significantly associated with morphology, supporting heritability of shape variation. These results support the inference of evolved functional differences among localities, and the importance of hydroclimate in early stages of diversification. We expect that substantial evolutionary responses will be required in tropical rainforest endemics to mitigate local fitness losses due to changing climates.

Adaptation of plasticity to projected maximum temperatures and across climatically defined bioregions.

Resilience to environmental stressors due to climate warming is influenced by local adaptations, including plastic responses. The recent literature has focused on genomic signatures of climatic adaptation, but little is known about how plastic capacity may be influenced by biogeographic and evolutionary processes. We investigate phenotypic plasticity as a target of climatic selection, hypothesizing that lineages that evolved in warmer climates will exhibit greater plastic adaptive resilience to upper thermal stress. This was experimentally tested by comparing transcriptomic responses within and among temperate, subtropical, and desert ecotypes of Australian rainbowfish subjected to contemporary and projected summer temperatures. Critical thermal maxima were estimated, and ecological niches delineated using bioclimatic modeling. A comparative phylogenetic expression variance and evolution model was used to assess plastic and evolved changes in gene expression. Although 82% of all expressed genes were found in the three ecotypes, they shared expression patterns in only 5 out of 236 genes that responded to the climate change experiment. A total of 532 genes showed signals of adaptive (i.e., genetic-based) plasticity due to ecotype-specific directional selection, and 23 of those responded to projected summer temperatures. Network analyses demonstrated centrality of these genes in thermal response pathways. The greatest adaptive resilience to upper thermal stress was shown by the subtropical ecotype, followed by the desert and temperate ecotypes. Our findings indicate that vulnerability to climate change will be highly influenced by biogeographic factors, emphasizing the value of integrative assessments of climatic adaptive traits for accurate estimation of population and ecosystem responses.

De novo transcriptome assembly and annotation for the desert rainbowfish (Melanotaenia splendida tatei) with comparison with candidate genes for future climates.

Transcriptomics via RNA-seq has rapidly emerged as a powerful tool for ecological and evolutionary studies, enabling genome-scale studies of adaptation via regulation of global gene expression. Here we present a de novo transcriptome for the desert rainbowfish (Melanotaenia splendida tatei) based on individuals sampled in the Lake Eyre Basin, Australia's arid zone river system. Recently developed methods in RNA-seq and bioinformatics were used for sequencing, assembling and annotating a high-quality liver transcriptome suitable for studies of ecology and adaptation in desert rainbowfish. Transcript annotation in UniprotKB using BLASTx assigned unique protein matches to ~47% of 116,092 Trinity genes, while BLASTp assigned unique protein matches to ~35% of 62,792 predicted protein-coding regions. A full Trinotate annotation report is provided for predicted genes and their corresponding transcripts. Annotations were compared with previously identified genes for transcriptional regulation and heritable plasticity in future climates in the subtropical rainbowfish (M. duboulayi), finding ~57% of these candidate genes present in the desert rainbowfish transcriptome. We discuss the utility of transcriptomics methods for ecological studies of adaptation, while emphasising a range of methodological considerations for dealing with transcriptome datasets. This newly assembled transcriptome is expected to help elucidate mechanisms for adaptation to high temperatures and a variable climate in desert aquatic fauna.

It doesn't happen here: eating disorders in an ethnically diverse sample of economically disadvantaged, urban college students.

The bulk of eating disorder studies have focused on white, middle-upper class women, excluding ethnically and economically diverse women and men. Accordingly, our knowledge of prevalence rates and risk factors is reliant on this narrow literature. To expand upon the current literature, we examined eating disorders in ethnically diverse low-income, urban college students. We surveyed 884 incoming freshmen during an orientation class to assess the frequency of eating disorder diagnosis and the risk factors of child physical abuse and sexual abuse before and after age 13. We found 10% of our sample received an eating disorder diagnosis, 12.2% of the women and 7.3% of the men. The majority of these students were Latino/a or "other," with White women receiving the fewest diagnoses. For all women, both child physical abuse and both indices of sexual abuse contributed equally to the development of an eating disorder. For men only the sexual abuse indices contributed to an eating disorder diagnosis. These results indicate that ethnic minority populations do suffer from relatively high rates of self-reported eating disorders and that a history of trauma is a significant risk factor for eating disorders in these diverse populations of both women and men.