La détermination du sexe chez les barbeaux (Osteichthyes, Cyprinidae, Barbus)

The origin and the phylogeny of the genus Barbus are still debated. Diploid and tetraploid species in Barbus are found in Africa and Asia whereas tetraploid species only are present in Europe. Sex determination would be interesting to study in these different species from an evolutionary viewpoint. So at first sex determination has been studied in the common barbel (Barbus barbus), an European tetraploid species. The sex determining mechanism XX-XY is the general rule in Cyprinids, with female homogamety (XX) and male heterogamety (XY). To test the hypothesis of female homogamety in common barbel, sex ratio of experimental gynogenetic offspring was analysed. Almost 50% males were observed in all gynogenetic lines produced whereas 100 % females were expected in case of female homogamety. When gynogenetic males were crossed with control females their progenies showed sex ratios close to 1:1. When gynogenetic females were crossed with control males their progenies were 100 % females. These results proved female heterogamety (ZW) and male homogamety (ZZ) in the common barbel.