Abalones, which belong to the class Gastropoda, are an important commercial species that are currently cultivated in many coastal regions. Extensive inbreeding and/or bottleneck effects have led to a decline in the genetic variation of these species and resulted in an outbreak of disease and massive mortality. Therefore, it is important to develop a system to monitor genetic variations in brooding stock of abalone. However, phylogeny and genetic variation of abalone in China remain unknown, little information is available for abalone in the world. In my study, Random Amplified Polymorphic DNA (RAPD) and 18S rDNA sequecing were used to study the genetic variations between farmed and natural populations, and different species of abalones in China. RAPD permits rapid and cost-effective det...[ Read more ]

Abalones, which belong to the class Gastropoda, are an important commercial species that are currently cultivated in many coastal regions. Extensive inbreeding and/or bottleneck effects have led to a decline in the genetic variation of these species and resulted in an outbreak of disease and massive mortality. Therefore, it is important to develop a system to monitor genetic variations in brooding stock of abalone. However, phylogeny and genetic variation of abalone in China remain unknown, little information is available for abalone in the world. In my study, Random Amplified Polymorphic DNA (RAPD) and 18S rDNA sequecing were used to study the genetic variations between farmed and natural populations, and different species of abalones in China. RAPD permits rapid and cost-effective detection of polymorphisms and genetic markers in different species and populations. A total of 65 ten-base primers were screened and 20 primers yielded amplification products. Three positive primers that gave highly reproducible RAPD patterns were selected for the analysis of genetic variations between the populations of Haliotis diversicolor from Taiwan (farmed) and Xiamen (natural). Also 3 positive primers that gave out polymorphism between different species were selected to determine the genetic variations among H. diversicolor, H. asinina, H. discus hannai and H. varia varia. Populations from Xiamen and Taiwan were found to be the same species with the similarity values of 0.84 ± 0.168 to 0.95 ± 0.087 and population from Taiwan showed a significantly higher similarity value (0.96 ± 0.085) between individuals. H. asinina and H. varia varia showed the highest similarity value (0.67 ± 0.19) while H. asinina and H. discus hannai showed the lowest similarity value (0.30 ± 0.09) among the 4 species. Three pairs of primers with complementary to the conserved termini of 18S rDNA gene were used to amplify the gene. Results showed that all the three pair primers were able to amplify DNA fragment with the size about 1.8 kilobase pairs from all the four species in which the size is similar to those found in other mollusks.