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This Week in PNAS: Nov 13, 2013

Editor's Note: Some of the articles described below are not yet available at the PNAS site, but they are scheduled to be posted some time this week.

In a study slated to appear online this week in the Proceedings of the National Academy of Sciences, a team led by Daniel Rokhsar, with the US Department of Energy's Joint Genome Institute and the University of California, Berkeley, profiles meiotic recombination patterns in the monkeyflower plant, Mimulus guttatus. Through deep sequencing on pooled samples from a wild M. guttatus population — together with reference genome sequencing on a single monkeyflower line — the researchers detected crossover events in the flowering plant's genome and defined around 13,000 recombination hotspots. Recombination events appeared more apt to occur around the start of monkeyflower genes, study authors say, but declined in other coding sequences and in introns.

Researchers from the US and Switzerland used single-molecule real-time sequencing to track methylation dynamics across the Caulobacter crescentus genome during five stages of the alpha-proteobacteria's cell cycle. In the process, they identified more than 4,500 spots in the genome where methylation shifted during DNA replication and dozens of other sites that appeared protected from such methylation changes. The work also pointed to new methylation motifs in the microbial genome, the investigators note, along with methyltransferase enzymes regulating some of those sites.

Finally, a Japanese group relied on a genome-wide association study strategy to track down four variants that seem to influence conception success in dairy cows. By comparing SNP profiles in hundreds of diary cows with low and high conception rates, the researchers narrowed in on half a dozen variants with apparent ties to this reproductive process. Four of those SNPs fell in and around known genes, researchers report, including the gap junction-related genes PKP2 and CTTNBP2NL and genes called SETD6 and CACNB2, which contribute to hormone secretion in the cows. Our sister publication GenomeWeb Daily News has more on the study, here.