In this week's Science, a team of Spanish scientists publishes a study showing that roundworms exposed to high temperatures undergo genetic changes that are passed to their offspring for many generations through both sperm and egg. Previous work has shown that starvation or exposure to high temperatures can alter the expression of messenger RNA in Caenorhabditis elegans and that this effect can persist in up to three generations. In the new study, the researchers discovered that when a single generation of C. elegans was exposed to high temperatures, increased expression of a particular gene occurred in their offspring, but not in additional generations. But when C. elegans were exposed to this increased temperature for five generations, it took 14 generations for the expression of a multi-copy transgene to return to baseline. By crossbreeding roundworms, they determined that inheritance of these genetic alterations occurred through both eggs and sperm. The findings demonstrate the existence of long-lasting epigenetic memory of environmental change in this species.
And in Science Translational Medicine, an international team of scientists describes the use of transcriptome sequencing to diagnose genetic disorders that couldn't be identified by DNA sequencing. They used RNA sequencing on muscle biopsy samples from a cohort of 50 patients with unidentifiable conditions and were able to assign a cause to 17 previously undiagnosed muscular dystrophies. In some cases, they identified disease-causing genetic changes that are difficult to pinpoint using DNA sequencing, and also linked a new mutation to one specific form of muscular dystrophy in a larger cohort of patients without confirmed diagnoses. The study, the authors write, "represents a large systematic application of transcriptome sequencing to rare disease diagnosis and highlights its utility for the detection and interpretation of variants missed by current standard diagnostic approaches." GenomeWeb has more on this here.