Detection of ayu [Plecoglossus altivelis] sex-linked DNA markers using homologous clones

In order to detect sex‐linked DNA markers, linkage analysis was performed in each of three ayu half‐sib families using 32 amplified fragment length polymorphism primer combinations, four microsatellite DNA primer sets and phenotypic sex (male). In each family the sex‐determining locus appeared in a distal position on one of the linkage groups in which the D7‐141* marker was strongly associated with male gender. The D7‐141* marker was amplified in all of the male ayu (100%), and 8.7% of the female ayu. The D7‐141* marker was detected in all male ayu at a level similar to that in the 40 wild individuals. These results suggest that the D7‐141* marker is a male‐specific marker linked with the sex‐determining locus of the male in amphidromous ayu.