Evidence of genetic differentiation in cigar wrasseCheilio inermis(Labridae) within the western Indian Ocean

Abstract

Patterns of genetic structure and connectivity of the monotypic cigar wrasse Cheilio inermis within western Indian Ocean (WIO) are poorly understood. Whether the species exists as a single panmictic population across the WIO is unclear. Sequence data were generated from two mitochondrial genes (cytochrome b and ATPase 6) and one nuclear intron (S7 intron I). High levels of haplotype and allelic diversity (h = 0.88–0.98; A = 0.95–0.98), along with low nucleotide diversities were observed across all markers. The pairwise ΦSTvalues indicated differentiation of Tanga from the four WIO localities (Inhaca, Nosy Bé, Gazi, and Shimoni), as well as differentiation between the northernmost WIO localities. AMOVAs indicated high differentiation among defined locality groups, whereas nuclear gene analysis found little differentiation among groups. The observed genetic differentiation in C. inermis could be caused by oceanic barriers, and by limited larval dispersal with the pelagic larvae possibly settling near their parental origin and promoting differentiation.