In this week's Science, scientists from the Salk Institute describe how mouse pups that receive less maternal care have more transposons in a certain part of the brain, suggesting that early life experience can influence somatic variation in the genome. In the study, the investigators focused on long interspersed nuclear element–1 (L1) retrotransposons, and found that pups receiving less maternal care exhibited noticeably more transposon replication in the hippocampus. Notably, the effect was not identified in all tissues, meaning it is unlikely to be a result of inherited differences in L1 copy number. Additional analysis suggests that methylation of transposons may play a role in this phenomenon. GenomeWeb has more on this, here.
Also in Science, an international team of scientists reviews the relationship between the gut microbiome and cancer treatment as part of a cancer immunotherapy special issue. They highlight studies showing that antibiotic can hinder efficacy of immune checkpoint therapy, while the presence of certain gut microbes is associated with superior efficacy. "Future strategies of precision medicine will likely rely on novel diagnostic and therapeutic tools with which to identify and correct defects in the microbiome that compromise therapeutic efficacy," the authors write.