amphioxus

European amphioxus, a small marine chordate prized in evolutionary studies, shows high genetic diversity across its range yet remains a single connected population, and ocean currents are credited with linking distant populations and dispersing larvae widely enough to prevent genetic isolation. The finding highlights how physical oceanography shapes genetic structure in widely distributed marine species.

Scientists have sequenced the amphioxus genome, a close living relative of vertebrates, and found unusually high heterozygosity — large genetic differences between chromosome pairs. The extreme variation allowed researchers to study recombination patterns and genome evolution in fine detail, offering clues about how genetic shuffling works and how it shaped the ancestors of all vertebrates, including humans.