New research has identified DNA exchange as a major factor in the broad diversity of Heliconius butterflies, highlighting the importance of hybridization to species evolution. In the study, which appears in this week's Science, an international research team generated genome assemblies for 20 major Heliconius species, as well as three related genera. Using a novel statistical method, the investigators find a significant role for hybridization on the evolutionary history of Heliconius across the sampled genomes, although the effect varies with factors such as gene density and genome architecture. The authors also identify a previously undetected inversion, likely transferred between lineages by introgression, that spans a genetic hotspot of wing color pattern diversity in the related Lepidoptera. "Just as sex aids adaptation within species, occasional introgression and recombination among species can have major long-term effects on the genome, contributing variation that could fuel rapid adaptive divergence and radiation," the researchers conclude.
A growing body of evidence suggests that gut microbiota may influence neurodevelopment and social behaviors in diverse animal species, a team of US and European scientists write in a review in Science this week. "A new appreciation of host-microbe interactions has led to unprecedented focus on the microbial world in animals," they write. And as new research identifies roles for gastrointestinal microbiota in varied biological processes including neurological ones, there are hints that host-microbiota interactions may have influenced the evolution of social behaviors. "Expanding microbiome-sequencing analyses across the animal kingdom remains a major challenge but will allow for greater insight into how social behavior interacts with microbial symbionts within and across diverse ecosystems," which could help in understanding the causal mechanisms underlying sociability and point to therapeutic strategies for social disorders in humans, they say.