In PLoS Genetics this week, researchers in the UK report on genetic diversity in cytokines that they say is associated with immune variation and resistance to pathogens. The team examined a natural population of field voles to demonstrate "strong effects of genetic variation at cytokine loci both on host immunological parameters and on resistance to multiple pathogens." The researchers found that these effects were primarily localized to three cytokine genes — interleukin 1 beta, interleukin 2, and interleukin 2 beta. "Our results demonstrate that genetic diversity at cytokine loci is a novel and important source of individual variation in immune function and pathogen resistance in natural populations," the authors write.
Another team of UK researchers reports in PLoS One a complete genome characterization of a novel 26th bluetongue virus serotype from Kuwait. Although there are 24 distinct bluetongues virus serotypes that have been recognized for decades, two new serotypes have recently been identified. Here, the researchers report the entire BTV-26 genome sequence — it was found to share a common ancestor with BTV-25, recently identified in Switzerland. However, the team adds, there is a higher level of variation in the nucleotide sequence of Seg-7 in BTV-26 that suggests "strong conservation pressures on the protein of these two strains, and that they diverged a long time ago."
In PLoS Biology this week, researchers from the University of Chicago report data that demonstrate that new genes associated with brain development are rapidly recruited into the human genome. The team found that there is a significantly larger portion of young genes expressed in the fetal or infant brain of humans compared to mice and that "more young genes in humans have expression biased toward early developing brains than old genes." In addition, the researchers observed that the young genes are up-regulated in the early developing human brain have diverse functional roles. "These lines of evidence suggest that positive selection for brain function may have contributed to the origination of young genes expressed in the developing brain," the authors write.
Finally in PLoS Genetics this week, researchers in Austria say that genetic rearrangements can modify chromatin features at epialleles. The team analyzed both active and inactive epialleles found at a transgenic insert with a selectable marker gene in Arabidopsis, and found that "both converse expression states are stably transmitted to progeny." In addition, after mutagenesis by T-DNA transformation of plants carrying the silent epiallele, the team found new active alleles. "These cis-mutations caused different degrees of gene expression stability depending on the nature of the sequence alteration, the consequences for transcription and transcripts, and the resulting chromatin organization upstream," the authors write. "This illustrates a tight dependence of epigenetic regulation on local structures and indicates that sequence alterations can cause epigenetic changes at some distance in regions not directly affected by the mutation."