The highly heterozygous European amphioxus (Branchiostoma lanceolatum) at the edge of panmixia.

European amphioxus (Branchiostoma lanceolatum) exhibits an exceptionally high genomic heterozygosity of 2.73%, indicating extensive genetic diversity across its range.

• Why it matters: Understanding the genetic diversity of amphioxus is crucial because it sheds light on their evolutionary potential and population connectivity, which are vital for conservation and ecological studies.
• What they did: Researchers sequenced genomes from multiple individuals at Atlantic and Mediterranean sites, revealing minimal population differentiation despite geographic separation, and used phylogenetic and simulation analyses to identify large effective population size and larval dispersal as key factors.
• The result: The findings demonstrate that ocean currents facilitate long-distance larval dispersal, maintaining a near-panmictic population structure and enabling high genetic diversity across broad ecological ranges.