A detailed linkage map of Medaka, Oryzias latipes: Comparative genomics and genome evolution

We mapped 633 markers (488 AFLPs, 28 RAPDs, 34 IRSs, 75 ESTs, 4 STSs, and 4 phenotypic markers) for the Medaka Oryzias latipes, a teleost fish of the order Beloniformes. Linkage was determined using a reference typing DNA pan el from 39 cell lines derived from backcross progeny. This panel provided u nlimited DNA for the accumulation of mapping data. The total map length of Medaka was 1354.5 cM and 24 linkage groups were detected, corresponding to the haploid chromosome number of the organism. Thirteen to 49 markers for e ach linkage group were obtained. Conserved synteny between Medaka and zebra fish was observed for 2 independent linkage groups. Unlike zebrafish, howev er, the Medaka linkage map showed obvious restriction of recombination on t he linkage group containing the male-determining region (Y) locus compared to the autosomal chromosomes.