In Cell this week, a team from the Massachusetts Institute of Technology and the Whitehead Institute for Biomedical Research takes a look at DNA methylation marks that differ by parent-of-origin in developing or adult mice. The researchers used a fluorescent reporter system to follow methylation from an imprinted promoter at the chromosome 12 locus Dlk-Dio3 in mouse embryos and adult mice. "Surprisingly, methylation changes at the Dlk1-Dio3 [differentially methylated region] were found to be dynamic in most tissues of the embryo and postnatal animal," they write. "In particular, methylation imprints varied at the single-cell level during adult neurogenesis, resulting in inter-individual diversity and epigenetic variability."
Researchers from the University of Cambridge and other international centers describe efforts to detect anticancer compounds using a collection of 83 tumor xenografts derived from patient breast cancer samples. Using genome sequencing, array-based expression profiling, and copy number analyses, the team demonstrated that tumor explants growing in immunodeficient mice or short-term cell cultures typically maintained mutation patterns and intra-tumor heterogeneity found in the original tumor. Based on these findings, the investigators argue that the patient-derived tumor xenograft set provides an opportunity to do high-throughput screens for drug response or resistance.
Finally, a team from Belgium and the US reports on patterns detected in Saccharomyces cerevisiae strains that have been domesticated for beer production. The researchers sequenced the genomes of 157 strains of S. cerevisiae used for lab work or for industrial production of beer, wine, bread, bioethanol, spirits, and/or sake. From patterns within the genome sequences, which were analyzed in relation to yeast sources and phenotypes, they saw evidence for beer yeast domestication going back hundreds of years, leading to selection for features such as stress tolerance and sugar utilization. Our sister publication GenomeWeb Daily News has more on the study, here.