Differential gene flow between populations of Mytilus galloprovincialis distributed along Iberian and north African coasts

Resumo

This population genetics study on Mytilus galloprovincialis aims to clarify whether northern Moroccan populations fit into the biogeographical pattern of Iberian populations characterized by a main genetic discontinuity at the Almería - Orán Oceanographic Front (AOOF). We report a reduced gene flow between northern Moroccan mussels distributed at both sides of Gibraltar Strait and a limited gene flow between Iberian and Moroccan populations in the Alboran Sea. These results observed with microsatellites do not fully match previous ones where Moroccan populations from Alboran did not differ from other Atlantic populations. INTRODUCTION Previous studies using molecular markers such as allozymes (Sanjuan et al., 1994), mtDNA (Quesada et al., 1995), and microsatelites (Diz & Presa, 2008) have shown the existence of two differentiated population sets of Mytilus galloprovincialis in Iberia, one extending in continuity from the Cantabric Sea (NE Iberia) to the Alboran Sea (SE Iberia), and another one in the Mediterranean. The oceanographic properties of the Almería - Oran Oceanographic Front (AOOF; Tintoré et al., 1998) have been proposed as the causative force of such divide i.e. acting as an effective barrier to gene flow between those population sets. The present work aimed to clarifying genetic status of Northern Moroccan populations of M. galloprovincialis in the Alboran Sea using microsatellite markers, i.e., to test if they fit into the Iberian biogeographical pattern characterized by two gene pools distributed at both sides of the AOOF exclusion zone, respectively.