Genetic diversity and population structure in native and introduced populations of the Artemia franciscana (Crustacea, Anostraca) in Australia
Recent studies revealed two distinct invasion pathways of Artemia franciscana from its native range in North America to Eurasia. The potential source of the newly established populations in Eurasia mainly derived from two commercially sources in USA; Great Salt Lake (GSL) and San Francisco Bay (SFB). In the present study, we are determined the phylogenetic relationships, haplotype network and population genetic structure of Artemia from native (North America) and introduced regions in Australia using sequence variation in a mitochondrial gene (cytochrome c oxidase subunit I) COI marker. Phylogenetic trees (ML/BI) reveal the colonization of A. franciscana in four geographical regions whereas, parthenogenetic lineages were observed only in two regions of Australia. Genetic diversity for all introduced Australian populations reveals a higher value (HE = 0.737±0.038) than those in GSL (HE = 0.649±0.065), suggesting multiple introductions with founder effects. The analysis at the regional level shows that the invasion of A. franciscana is associated with a loss of genetic diversity, indicating bottleneck effects. Tajima test shows a non-significant value, indicating that the populations are under equilibrium without selection. The genetic partitioning reveals that most of genetic variations occurred among populations (70.87%). The distribution of genetic diversity and pattern of genetic differentiation suggests the colonization of A. franciscana from native regions in North America into Australia (pairwise FST = 0.7). Phylogenetic network points to multiple invasions from several genetically different sources in Americas and Eurasia, which seems to facilitate the widespread colonization success of A. franciscana into Australia. This study signifies extensive human-mediated introductions which influence the pattern of genetic diversity throughout Australia.