The Application Of AFLP In Species Identification And Genetic Structure Analysis In Scallop

The AFLP technique is used to screen the specific markers of the four main scallop species bred in China and to analyse the genetic structure of Zhikong scallop (Chlamys farreri), Huaguizhikong scallop (Chlamys nobilis) and their Fl reciprocal hybrids.Zhikong scallop, Huaguizhikong scallop, Japanese scallop (Patinopecten yessoensis), Bay scallop (Argopecten irradians) belong to the three genus of Pectinidae. There are some difference in the biological character and genetic base among the four scallop species. According to the result, only 105 of total 510 loci are consistent in the four species. Zhikong scallop and Huaguizhikong scallop belong to the same genus, so the genetic relation of them should be the most close, which is proved through the systematic tree constructed by the UPGMA method. The specific markers of Zhikong scallop, Japanese scallop and Bay scallop can be used for the species identification. As to Huaguizhikong scallop, it can be identified by the combination of the above specific markers and the 3 markers shared by Bay scallop.In this study, most of the dominant loci from Zhikong scallop and Huaguizhikong scallop can be amplified in their hybrid offspring, especially the 13 of 17 specific markers in Huaguizhikong scallop is hereditable. According to the results, the hybrid offspring inherit genetic material from not only the male parent but also the female parent, and the genetic structure of the offspring is significantly partial to Zhikong scallop (the female parent), the mechanism is now in research.It is found that most of the amplified AFLP markers are coincident with the genetic relation, but a few of them are not, including the 8 makers only existing in parents' population and the 10 only existing in offspring population. The amplified AFLP markers only existing in parents' population are probably caused by thereciprocity of the parental homologous chromosome, which makes the loci that can be identified by the restriction enzymes be modified or hidden and can not be amplified.It is important to obtain the specific markers for the identification of parent and offspring population which is similar in morphological character. In the AFLP markers from E32M54, E35M61 and E44M61, only E44M61-22 is specific in Huaguizhikong scallop, which can be combined with E32M54-111 to identify the three populations.In order to deeply study the genetic mechanism of hybrid offspring, AFLP is used to analyze the genetic structure of the three populations, to study the difference in genetic structure, the distributing and trend of genetic markers, to find the specific markers of the three populations. Hope that it could provide reference for the scallop hybrid breeding.