Population connectivity of chaetognath Eukrohnia hamata

This study examined the population genetic diversity, structure and connectivity of the chaetognath, Eukrohnia hamata, based on sampling from six regions of the Arctic Ocean. Specimens were analyzed for DNA sequence variation of a 650-bp region of the mitochondrial cytochrome oxidase I (mtCOI) gene and for genomic Single Nucleotide Polymorphisms (SNPs) detected by double-digest Restriction-Associated Digestion (ddRAD). Both analyses confirmed high levels of gene flow among the regions, and ddRAD SNP analysis supported the genetic distinctiveness of two population clusters: Atlantic-Arctic versus Pacific-Arctic. Removal of SNPs subject to selection resulted in slightly higher probability of three clusters, and suggested the possibility of local adaptation of regional populations of E. hamata. Comparative analysis of revealed evidence that random selection of subsets of SNPs can result in marked differences in numbers and distributional patterns of clusters and associated variation in F-statistics.