Molecular Systematics On Germplasm Resources Of Antheraea Pernyi

Molecular systematics on germplasm resources of oak silkworm, Antheraea pernyi , including genetic diversity, cultivar taxonomy and microevolution within species, were investigated using Random Ampified Polymorphic DNA (RAPD), mtDNA sequence analysis and population genetic analysis. The genetic diversity among individuals within cultivar, cultivars, populations, and between oak silkworm and wild oak silkworm were detected. The results were as follows:1 Genetic diversity in cultivar of oak silkwormRAPD analysis was used to assess genetic variability in four cultivars of oak silkworm cultivars (He41, Siqing, Qinghuangl, Xinghuang) . Fourteen arbitrary 10-mer primers amplified 143 DNA fragments, 138 (96.5%) of which were polymorphic. The DNA polymorphism of different individuals within cultivar reached 45.8%-49.4%. The genetic distance value of different individuals within cultivar were 0.133-0.238; of different individuals among different cultivars were 0.215-0.382. The cluster analyses which were performed with UPGMA and NJ methods showed that all individuals were grouped according to its cultivar.The genetic variation distribution within and between cultivars were analyzed using polymorphism ratio and PopGen software. 60% DNA polymorphism was derived from different individuals within cultivar, and 40% from between cultivars.The total gene diversity (Nei's index) was 0.2737, with a distribution within (52.51%) and between cultivars (47.49%); The results snowed that the present oak ouoworm cultivai was still a mixed population wirn lower purity.We discussed the possible reasons to lower purity of the cultivars, and thought that the results were probably cased by the shorter domestication history, reared-in-the-wild and mixed seed selection, et al. The genetic variation distribution within and between cultivars was to some extent related to the domestication history. We put forward a new viewpoint that the purity of seed selection keeps the balance with the DNA polymorphism demand. The research aim at oak silkworm seed selection was to determine how to keep the balance between improving cultivar purity and keeping the genetic diversity within cultivar.2 Genetic relationships of gerniplasm resources of A.pernyiThe genetic relationships of 68 A. pernyi cultivars were analyzed by random amplified polymorphic DNA (RAPD). A total of 296 DNA fragments were amplified by 33 primers selected among A. pernyi cultivars, 269 of which (90.88%) were polymorphic. Only nine (12.68%) of A. pernyi cultivars used had one or more cultivar-specific markers. The value of pairwise genetic distance were from 0.120 to 0.324, and most of them were in the range of 0.200 to 0.300. There were 99.05% of the cultivar pairs with parewise genetic distance less than 0.300, which had great genetic similarity. The percentage of 0.95% of cultivar pairs had better genetic differece, with pairwise genetic distance exceeding 0.300. Generally, there was great genetic similarity among A. pernyi cultivars.A dendrogram was constructed by Neighbor-Joining method. The A. pernyi cultvars used were classified into 6 genetic groups. The cultivars in a group were closely related to their geography distribution , and clustered into groups in a lower level and that the effect of selection on A. pernyi cultivar was obvious. We thought that these results were probably caused by the shorter radiation and differentiation history, the shorter artificial selection time and widely cultivar exchange among different producer area. It was reflected that A. pernyi, as a domesticated and reared-in-the-wild, was subjected to both artificial and natural selection. By combining the geography distribution clustering characteristics and cluster level, the 68 A. pernyi cultivars were divided into 3 larger groups: Shandong group, Henan group which included Henan cultivars and Guizhou cultivars , Liaoning group which included Liaoning cultivars, Jilin cultivars, Neimenggu cultivars and Chaoxian cultivars.Compared with different data analysis methods, outgroup...