Development of genetic markers of tropical abalone in Thailand

Abstract

Genetic diversity of three species of abalone in Thailand; Haliotis asinina, H. ovina, and H. varia were analyzed by RAPD-PCR and PCR-RFLP of 18S and 16S rDNAs. Several species-specific RAPD fragment was found using primers INS, YN73, and M13. Restriction analysis of 18S rDNA (nuclear marker) with Alu I, Tag I and Hae III and 16S rDNA (mitochondrial marker) with BamH I, EcoR I, Hae III and Alu I gave 12 and 13 digestion patterns for 18S rDNA and 16S rDNA, respectively. A total of 49 composite haplotype were observed. Genetic distances between pairs of composite haplotypes within species were lower than those between species. A UPGMA dendogram constructed from divergence between composite haplotypes, samples and species revealed separate gene pools of these abalones. The H. asinina alone showed closer genetic relationships with H. ovina than H. varia. Geographic heterogeneity analysis and Fst estimate indicated the existence of population structure ofeach abalone. Disregarding H. varia due to small sample sizes, strong genetic differentiation was observed in H. ovina whereas partial differentiation was observed between the Philippines and the remaining sample (P<0.0021). The 16S rDNA of individual representing 10 composite haplotypes of three abalone species were cloned. Comparing and sequenced. The aligned sequences indicated the possibility to develop species-specific PCR from these sequences. A neighbor-joining tree constructed from sequence divergence of these sequences allocted relationships of sequences according to species origins of abalone