Mitochondrial DNA reveals population structuring in Macrodon atricauda (Perciformes: Sciaenidae): a study covering the whole geographic distribution of the species in the southwestern Atlantic

Abstract

We investigated the genetic structure and diversity of M. atricauda, based on 266 specimens collected off the coast of southern Brazil and Argentina at seven locations, covering the whole geographic distribution of this species. A DNA sequence alignment of 904 base pairs of the mitochondrial Control Region revealed a total of 85 haplotypes. F_ST analyses suggest that M. atricauda does not comprise a single demographic stock. Two different genetic units are identified, which possibly are related to ecological adaptations of the species within its range. Genetic diversity, Bayesian analysis of population structure, and significant negative results for the D and FS tests indicate that M. atricauda populations have undergone recent expansion. The spatial distribution of genetic variation seems to be related to historical colonization from south to north, followed by expansion.

• Control region
• genetic structure
• Macrodon atricauda
• southern king weakfish
• southwestern Atlantic

Acknowledgements

Funding for this research was provided by CNPq (grants 306233/2009-6 to IS and 306233/2009-6 to HS) and FAPESPA (PRONEX 2007 to HS). Rosa Rodrigues was supported by a PhD scholarship from CNPq (141224/2008-8).