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Germplasm of the fetched Paralithys lethostigma was analyzed using karyotype study, isozyme techmique and RAPD technique. And partial DNA sequences of mitochondrial gene were amplified by PCR and sequenced. The main results were shown as follows:The karyotype of Paralichthys lethostigma was studied through the chromosome preparations obtained from gill cells or fin cells by the method of staining in the colchicines with low permeating and air drying method. The results showde that the diploid chromosome number of the species is 2n = 48 and its karyotype formulae is 2n = 48, 48t with NF = 48. The polyploidy chromosomes and the sex chromosomes were not found and there was no visible evidence of the satellites.Polyacrytamid gel electrophoresis (PAGE) was used to investigate the isozyme genetic variation of the Paralichthys lethostigma. 48 individuals were sampled and the muscle and liver were collectedfetched from each of the samples. The supernatant samples were used as the isozyme source and electrophoresis was carried out on vertical polyacrylamide gels in Tris-gly buffer system (TG, pH8.3) at 280 V for approximately 5 h at 4℃. The isozymes were analyzed by specific isozyme staining methods. Fifteen isozymes (i.e. MDH,LDH,ME,ADH,SDH,EST,POD,SOD,IDH,GDH,AMY,CAT,G6PD,PGM,PGI) were selected. The genetic variations were analyzed in terms of their locus number, structure, alleles etc. Altogether 33 loci were scored. Among the scored loci, 11 loci ( Me-1,Adh-1,Sdh-1,Sdh-2,Gdh-1,G6pd-1,Pgm-1,Idh-1,Cat-1,Pod-1 and Pgi-1 ) are polymorphic and the mean proportion of polymorphic loci (P) is 33.3 %. The mean effective number of alleles per locus (Ae) is 1.2196; the mean expected heterozygosity per locus (He) is 0.1219 and the mean observed heterozygosity (Ho) is 0.1547. In the mean time, the deviation indexes from Hardy-Weinberg equilibrum (d value) of polymorphic locus were tested. The results showed that the genetic diversity of Paralichthys lethostigma was higher
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