The Comparison on the Genotype of idh-1 Between Paralichthys olivaceus and Scophthalmus maximus

Paralichthys olivaceus and Scophthalmus maximus were two economic mariculture species in China. To study the relativity between the genotype of idh-1 and the growth indices, 141 Paralichthys olivaceus from the culture stocks in Rongcheng and Yantai in Shandong province, Beidaihe in Hebei province and 60 Scophthalmus maximus from Hangu of Tianjin were investigated by the isozyme electrophoresis and specific dying and their biological indices. The results showed that the idh-loci of both species were polymorphic, but the genotype was quite different: there were three genotypes of Paralichthys olivaceus (AA, BB and AB, identical with the dimer of IDH); thus there were two genotypes of Scophthalmus maximus (A1, A2) with 53 and 7 individuals, respectively. By the statistical analysis of gene frequency, Paralichthys olivaceus showed the heterozygote surplus and genetic bias in Hardy–Weinberg equilibrium. The chi-test explained that only the loci of idh-1 in Rongcheng expressed the significant bias in Hardy–Weinberg equilibrium, there were significant difference between the observational values of heterozygosity (\( {({\overline {\text{Ho}}})} \)) and Hardy–Weinberg expected heterozygosity (\({({\overline {\text{He}}})} \)) (P < 0.05). From the relationship between locus and growth triats, we found that the heterozygote(AB) of idh-1 have the growth dominance in comparison with homozygote (AA or BB). In the data of two groups of Scophthalmus maximus, the average value of the weight, length, and body height of the A2-individuals were all higher than those of A1. Compared to A1-individuals, the weight (group1)\height (group1 and 2) of A2-individuals have a significant difference(P < 0.01). This result has provided reference for the molecular marker-assisted breeding of Paralichthys olivaceus and Scophthalmus maximus.