抄録
We investigated variability in the size of restriction fragments of the rDNA region among 4 laboratory strains of the freshwater fish medaka including two wild-type fish and two pigmentation mutants. For this analysis, PCR-amplified 18S rDNA was used as a probe. DNA from 6 individuals of each strain was analyzed and significant variability in the restriction fragments was observed. The copy number of the 18S rDNA determined by dot-blot hybridization was also highly variable among individuals, from 120 to 2, 591. These results revealed considerable genomic polymorphism at this region in the medaka.
