Population genetic analysis of and (Nematoda, Anisakidae) from parapatric areas and their contact zone.

Genetic markers (ribosomal DNA and mitochondrial DNA) were used for molecular dissection of the populations. Host fish were caught off Moroccan coasts, where only is present, the sympatric area comprising Spanish coasts, and the Little Sole Bank fishing area from Nordeast Atlantic Ocean where the only present species is .). Sequence variations in the amplification products were then assessed indirectly by digestion with restriction endonucleases or directly by sequencing for 623 L3 larvae. The sequences were used to infer the relationships between the two species under study using various methodological approaches. We reveal the high genetic diversity of and . in both mitochondrial and nuclear genes. We detected 10 and 2 fixed differences between and in the Cox2 and ITS1, respectively. We found a proportion of putative hybrids below 20% with similar figures on the Atlantic and Mediterranean coasts. Moroccan hybrids were more similar to reflecting backcrosses between these mixed genotypes and his ancestor We discuss the possible interpretation of these putative hybrids.