In this week's PNAS Early Edition, the University of Washington's Jay Shendure and his colleagues report on their exome sequencing study of 23 prostate cancers derived from 16 different lethal metastatic tumors and three high-grade primary carcinomas, through which they uncovered a "spectrum of mutation frequencies in advanced and lethal prostate cancers." The team shows that "point mutations arising in coding regions of advanced prostate cancers are common but, with notable exceptions, very few genes are mutated in a substantial fraction of tumors," and describes a previously unrecognized subset of prostate cancers that it says exhibit "'hypermutated' genomes, with potential implications for resistance to cancer therapeutics." Our sister publication GenomeWeb Daily News has more on this study.
Elsewhere, Cornell University's Anna Savage and Kelly Zamudio show that, in frogs, "alleles of an expressed MHC class IIB locus associate with survival following Bd [Batrachochytrium dendrobatidis] infection" — a finding they uncovered through experimental Bd infections in lab-reared frogs derived from five populations that showed natural variation in susceptibility to the fungal pathogen.
An international team led by investigators at Belgium's Catholic University Leuven and Flemish Institute for Biotechnology deconstruct the "complex genetic architecture of Drosophila aggressive behavior" in a paper published online in advance in PNAS this week. In performing a "diallel cross among coisogenic Drosophila P-element mutations associated with hyperaggressive behavior," the team uncovered "extensive epistatic and pleiotropic effects on aggression, brain morphology, and genome-wide transcript abundance in head tissues." Further, the team says its study points to "evolutionarily conserved genetic mechanisms and neural signaling pathways affecting this universal fitness trait."
Investigators at the University of Minnesota and elsewhere report their characterization of sequence polymorphisms and linkage disequilibrium in the model legume Medicago truncatula using whole-genome sequence data. "Our analyses reveal that M. truncatula harbors both higher diversity and less LD than soybean (Glycine max) and exhibits patterns of LD and recombination similar to Arabidopsis thaliana," the authors write.