A PLOS One study supports the notion the cognitive ability has a heritable basis that involves variants of small effect in many different genes. Researchers from the University of Minnesota used information at roughly 2.5 million imputed or directly genotyped SNPs for a genome-wide association study of general cognitive ability in 7,100 Caucasian individuals who had been assessed for their cognitive wherewithal using IQ tests adjusted to reflect their age. Based on results generated with several different analytical strategies, the team concludes that general cognitive ability stems from a slew of variants that have infinitesimally small effects individually, but that add up to "substantial" heritability.
In PLOS Genetics, a University of California, Davis-led team takes a look at the genomes of halophilic archaea, or "haloarchaea," from parts of the archaeal phylogenetic tree that are still poorly characterized. The researchers selected and sequenced 59 osmoadaptive archaea from 17 genera, producing high-quality draft genome assemblies for the bugs. Using this data, as well as information from nearly two dozen haloarchaea sequenced previously, they tracked the distribution of protein families related to osmoadaptation in the haloarchaea and developed a model explaining how the organisms maintain appropriate ion transport when faced with variable osmotic environments. Based on the phylogenetic data available, the study's authors also argue against widespread horizontal gene transfer between bacteria and archaea during the advent of haloarchaea.
A team from the Max Planck Institute for Developmental Biology used bisulfite sequencing and RNA sequencing to track DNA methylation and its effects on transcription and transposon control in plants from three Brassicaceae family species for another PLOS Genetics study. Based on data for different tissues from Capsella rubella, Arabidopsis lyrata, and A. thaliana plants grown under various conditions, the researchers found evidence for DNA methylation shifts that reflect lineage-specific transposon patterns, tissue type, and temperature. Even so, they note that most sites in the genome that are subject to high levels of methylation do not seem to be conserved from one Brassicaceae plant to the next.