Studies on application of DNA finger-printing to estimation of genetic and environmental variances of some quatitative tarits in ayu, Plecoglossus altivelis

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1. DNA fingerprint (DNA-FP) was applied to comfirmation and identification of cloned fish induced by chromosome manupilation in ayu, Plecoglossus altivelis. We examined suitable enzyme/probe combinations and compared radioisotope (RI) and non-radioisotope (Non-RI) labelled probes to obtain clear DNA-FP.The best DNA fingerprintings were obtained by using YNZ 22,33.15 and 33.6 probes with HaeIII,MspI and HinfI restiction enzymes.In these DNA-FPs, the bands were separeted distinctly throughout the membrane in both higher and lower molecular weight regions. The DNA-FP bands obtained with the Non-RI labelled 33.15 probe were as intence and clearly separeted as those obtained with the RI method. All of the fragments were shared among individuals within a same clonal line, but the pattern of detected was significantly different between clonal lines.It was confirmed that DNA-FP is effective for identification of clonal lines. DNA-FP pattern by Non-RI labelled probe was clear enough to be widel … More y applicable to the studies on inbreeding and identification of individuals and families.2. Chromsome manipulated fish could be applied for estimation of heritability of any quantitative traits. Variances are increased in gynogentic fish because of segregation of genotypes in each locus controlling trait, but decreased in clonal fish by reduction of genetic variances. To estimates heritability, by appliing monozygous human twin model for the clonal ayu offsprings which were communally reared from the day hatched, heritability for the clonal population were estimated after the clonal lines were separated by DNA-fingerprinting identification. The values of heritability estimated for performance and morphological traits at 10 month age were relatively high. If the clonal lines were reared separately, tank and density effects (V_<EC1> + V_<EC2> ) may included in the variance between classes (sigma_B^2). The tank effects could be estimated by rearing clonal fish separately in the different tanks as a reference fish.It was concluded that clonal fish could be used as a control fish to estimate heritability of quantitative characters. The fish is also usable to separate common enviromenotal variance within a clonal line (V_<EC1> + V_<EC2> ) and enviromental variance between individuals with in a line (V_<EW> = sigma_W^2). Less