In an article published online on June 15, 2021 in PNAS, a team of researchers led by Columbia University’s Dustin R. Rubenstein, PhD, a Professor of Ecology, Evolution and Environmental Biology, found that within the same genus of marine snapping shrimp, Synalpheus, genome size and social behavior not only vary widely, but they are also co-evolving over time. The researchers have studied this group of snapping shrimp for years because they contain the only known marine animals that evolved to live in eusocial societies similar to those of ants and bees, where some individuals in a colony forgo their own reproduction to help rear the offspring of others. But it was only a few years ago that the research team discovered that snapping shrimp display extreme variation in genome size, with some species having very large genomes that are more than four to five times the size of the human genome.