Chromosome-Scale Selective Sweeps and Genomic Diversity in C. elegans
Andersen, Gerke et al., Nature Genetics
Researchers at Princeton University and elsewhere discuss the effects of chromosome-scale selective sweeps on genomic diversity in Caenorhabditis elegans. Taking a high-throughput selective sequencing approach on a collection of 200 wild C. elegans strains, the team found that the nematode's "genome variation is dominated by a set of commonly shared haplotypes on four of its six chromosomes, each spanning many megabases." Further, the team reports on its population genetic modeling experiments, which showed that "this pattern was generated by chromosome-scale selective sweeps that have reduced variation worldwide; at least one of these sweeps probably occurred in the last few hundred years," it writes.
This Week in PLoS
In PLoS Computational Biology, Australian researchers report that they developed a new method to study recombination in closely related HIV genomes. Their approach takes advantage of the small changes that can occur in the HIV genome that do not affect viral proteins or how infective the virus is. With this marker system, they then developed mathematical tools that measure the recombination rate while taking into consideration background recombination and template switching.
Duke researchers identified four gene regions connected with lipoprotein-associated phospholipase A2 levels in the blood, which is linked to atherosclerosis. Drawing on data collected as part of the Framingham study, they conducted a genome-wide association study of Lp-PLA2 activity and mass. The four loci that reached genome-wide significance were: the APOE/APOC1 region on chromosome 19, CELSR2/PSRC1 on chromosome 1, SCARB1 on chromosome 12, and ZNF259/BUD13 in the APOA5/APOA1 gene region on chromosome 11.
Viennese researchers looked into the role reversible histone acetylation has in transcriptional regulation of transposable elements. The researchers treated mouse cells with a histone deacetylase inhibitor and then monitored the expression levels of 10 different transposons. They found that VL30 transposons would reactivate when histone acetylation increased. The researchers also add that histone H3 phosphorylation, which occurs in response to stress, is needed for the acetylation-dependent activation of VL30 element. "Our finding that HDAC inhibition can reactivate VL30 elements in mice might indicate that other TEs or non-coding elements could also respond to an epigenetic therapy in humans," they write. "Therefore, careful evaluation of potential effects beyond the deregulation of single copy genes will be an important issue for future studies."
Finally, an editorial in PLoS Medicine from a group of medical journal editors discuss the principles of comparative effectiveness research as well as standards for CER. They write that "the principal goal of CER is to allow decision makers (patients, clinicians, purchasers, and policy makers) to make informed decisions on specific health practices" and that CER should be applied to a "broad range of interventions, tests, and strategies" as well as include "new data, old data newly analyzed, and systematic reviews of existing research." On the conducting and reporting end of CER, the editors encourage following established reporting as well as making CER studies freely available in a repository such as PubMed Central.