Micro-Satellite DNA Markers Associated with Resistance to Trembling Disease in Chinese Mitten Crab (Ericheirsinensis)
A total of 48 individuals of the Chinese mitten crab (Eriocheir sinensis)were used to study the association between micro-satellite DNA markers and their resistance to the trembling disease. The crabs used in this study were collected from an aquatic breeding farm in Yandu District, Yancheng city, Jiangsu Province in China. Twenty four of the crabs were collected from a pond heavily infested with trembling disease and these manifested clear signs of the disease while the remaining 24 crabs were collected from a pond free of the disease and these were all healthy. The Shannon Diversity Index was used to analyze the association of the individual marker alleles with resistance to the trembling disease. The results showed that the mean number of alleles (Na), the mean number of effective alleles (Ne), mean observed heterozygosity (Ho), mean expected heterozygosity (He), mean polymorphic information content (PIC) and mean Shannon index (I)in the individual populations were 4.2, 3.2, 0.6628, 0.6466,0.6221 and 1.2, respectively. Association analysis suggested that micro-satellite loci of 57, 62 and 254 were significantly associated with the sick population (P<0.05); micro-satellite loci of 57, 45, 358 and 977 were significantly associated with the healthy population (P<0.05). The micro-satellite loci that showed significant differences were tested for the associations between their genotypes and sick traits through multiple comparisons. The observed genotypes for sick individuals were AC (290/308) at loci of 57, BB (400/400) at loci of 62 and BB (340/340) at loci of 254. The favorable genotypes for healthy individuals were AD (290/314) at loci of 57, AA (290/290) at loci of 57, BB (390/390) at loci of 45, BC (315/321) at loci of 358 and BB (393/393) at loci of 977. This study will provide the theoretical basis for molecular marker-assisted breeding in Eriocheir sinensis in future.
