The effects of run-of-river hydroelectric power schemes on invertebrate community composition in temperate streams and rivers.

Run-of-river (ROR) hydroelectric power (HEP) schemes are often presumed to be less ecologically damaging than large-scale storage HEP schemes. However, there is currently limited scientific evidence on their ecological impact. The aim of this article is to investigate the effects of ROR HEP schemes on communities of invertebrates in temperate streams and rivers, using a multi-site Before-After, Control-Impact (BACI) study design.

Convergent evolution of sperm gigantism and the developmental origins of sperm size variability in Caenorhabditis nematodes.

Sperm cells provide essential, if usually diminutive, ingredients to successful sexual reproduction. Despite this conserved function, sperm competition and coevolution with female traits can drive spectacular morphological change in these cells. Here, we characterize four repeated instances of convergent evolution of sperm gigantism in Caenorhabditis nematodes using phylogenetic comparative methods on 26 species.

Ephemeral ecological speciation and the latitudinal biodiversity gradient.

The richness of biodiversity in the tropics compared to high-latitude parts of the world forms one of the most globally conspicuous patterns in biology, and yet few hypotheses aim to explain this phenomenon in terms of explicit microevolutionary mechanisms of speciation and extinction. We link population genetic processes of selection and adaptation to speciation and extinction by way of their interaction with environmental factors to drive global scale macroecological patterns. High-latitude regions are both cradle and grave with respect to species diversification.

The Effects of Run-of-River Hydroelectric Power Schemes on Fish Community Composition in Temperate Streams and Rivers.

The potential environmental impacts of large-scale storage hydroelectric power (HEP) schemes have been well-documented in the literature. In Europe, awareness of these potential impacts and limited opportunities for politically-acceptable medium- to large-scale schemes, have caused attention to focus on smaller-scale HEP schemes, particularly run-of-river (ROR) schemes, to contribute to meeting renewable energy targets. Run-of-river HEP schemes are often presumed to be less environmentally damaging than large-scale storage HEP schemes.

Comparative genomic analysis of upstream miRNA regulatory motifs in Caenorhabditis.

MicroRNAs (miRNAs) comprise a class of short noncoding RNA molecules that play diverse developmental and physiological roles by controlling mRNA abundance and protein output of the vast majority of transcripts. Despite the importance of miRNAs in regulating gene function, we still lack a complete understanding of how miRNAs themselves are transcriptionally regulated. To fill this gap, we predicted regulatory sequences by searching for abundant short motifs located upstream of miRNAs in eight species of Caenorhabditis nematodes.

Mainstreaming Caenorhabditis elegans in experimental evolution.

Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology.

Gene-flow between niches facilitates local adaptation in sexual populations.

In sexual populations, gene-flow between niches is predicted to have differential consequences on local adaptation contingent upon the nature of trade-offs underlying local adaptation. Sex retards local adaptation if antagonistic pleiotropy underlies trade-offs, but facilitates adaptation if mutation accumulation underlies trade-offs. We evaluate the effect of sex in heterogeneous environments by manipulating gene-flow between two niches in sexual and asexual populations using steady-state microcosm experiments with yeast.

Sex enhances adaptation by unlinking beneficial from detrimental mutations in experimental yeast populations.

Background: The maintenance of sexuality is a classic problem in evolutionary biology because it is a less efficient mode of reproduction compared with asexuality; however, many organisms are sexual. Theoretical work suggests sex facilitates natural selection, and experimental data support this. However, there are fewer experimental studies that have attempted to determine the mechanisms underlying the advantage of sex.