Screening of eye-position related genes with DD-RT-PCR and RDA in the hybrids between Japanese flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus

Flatfish or flounder moves one eye to change body proportion into vertebral asymmetry during metamorphosis, during which some become sinistral while others dextral. However, the mechanism behinds the eye-position has not been well understood. In this research, hybrids between Japanese flounder（♀） and stone flounder （♂） show mixed eye-location in both dextral type and sinistral type, and thus become good samples for studying the eye-migration, mRNAs from pro-metamorphosis sinistral and dextral hybrids larvae were screened with classical differential display RT-PCR （DD-RT-PCR） and representational difference analysis of cDNA （cDNA-RDA）; 30 and 47 putative fragments were isolated, respectively. The cDNA fragments of creatine kinase and trypsinogen 2 precursor genes isolated by cDNA-RDA exhibited eye-position expression patterns during metamorphosis. However, none of the fragments was proved to be related to flatfishes＇ eye-position specifically. Therefore, further studies and more sensitive gene isolated methods are needed to solve the problems.