Inconsistent phylogeographic pattern between a sperm dependent fish and its host: in situ hybridization vs dispersal.

The unusually high diversity of hybrid lineages in East-Qc as well as the spatial organization and the close genetic relationship with C. eos sympatric populations support the hypothesis that multiple hybridization events occurred in situ. These findings coupled to the near absence of the maternal species Chrosomus neogeaus suggest that the decline of this species could be the trigger event at the origin of the high rates of spontaneous hybridization in this region.