Invasion genetics of the Ciona intestinalis species complex: from regional endemism to global homogeneity

摘要: Determining the degree of population connectivity and investigating factors driving genetic exchange at various geographical scales are essential to understanding dynamics spread potential invasive species. Here, we explore these issues in highly vase tunicate, Ciona intestinalis, a species whose invasion history has been obscured by its poorly understood taxonomy genetics. Recent phylogenetic comparative genomic studies suggest that C. intestinalis is cryptic complex consisting least three We reconstructed phylogenies based on both mitochondrial (cytochrome c oxidase subunit 3—NADH dehydrogenase 1 region NADH 4 gene) nuclear (internal transcribed spacer 1) sequences, results which support four major phylogroups corresponding previously reported spA, spB spp. (spC) as well an undescribed (spD). While spC spD remain restricted their native ranges Mediterranean Sea Black Sea, respectively, (spA spB) have disjunct global distributions. Despite extensive interspecific divergences, identified low phylogeographical structure within two Haplotype network analyses revealed comparatively limited mutation steps among haplotypes each Population mtDNA fragments eight unlinked microsatellites illustrated relatively differentiation high regional continental Human-mediated dispersal coupled with for natural probably responsible observed homogeneity.