Investigators at Erasmus University Medical Centre in Rotterdam and the University of British Columbia report on a transcription-independent function for the polycomb group protein Posterior sex combs, or PSC, in regulating the destruction of cyclin B in a paper published online in advance in Science this week. "PSC appears to mediate both developmental gene silencing and posttranslational control of mitosis," the authors write, adding that "direct regulation of cell cycle progression might be a crucial part of the PcG [polycomb group] system’s function in development and cancer."
Massachusetts Institute of Technology's Eric Alm and his colleagues discuss genetic exchange among bacteria in the context of two recently diverged populations of ocean bacteria that they studied. "A few genome regions have swept through subpopulations in a habitat-specific manner, accompanied by gradual separation of gene pools as evidenced by increased habitat specificity of the most recent recombinations," Alm et al. write. "These findings reconcile previous, seemingly contradictory empirical observations of the genetic structure of bacterial populations and point to a more unified process of differentiation in bacteria and sexual eukaryotes than previously thought."
Elsewhere in this week's issue, an international research team led by Texas Biomedical Research Institute's Ian Cheeseman reports on a selective sweep on chromosome 13 that shows strong association with slow clearance rates as a result of artemisinin resistance in 715 parasites from Thailand they screened for SNPs and microsatellites in targeted genomic regions. Cheeseman et al. say that their study demonstrates "the efficacy of targeted association for identifying the genetic basis of adaptive traits."