Construction Of A AFLP Linkage Map Of Silkworm, Bombyx Mori And Clone For The Vitellogenin Gene From Antheraea Yamamai

Silkworm is an important model Lepidopteran insect with a long history of significant agriculture value. It is very important for researchers to construct the linkage map of silkworm to make great progress of molecular biology' and molecular-marker-assisted breeding of silkworm, and also necessary to obtain the molecular markers which are closely linked to the green cocoon gene, Gc. to improve the green cocoon line of silkworm for a relative short period.Until now the insects of Saturniidae are a kind of Lepidoptera insect with the biggest eggs. When the eggs of these insects is developing, the formation of yolk and the development of ovary are very much dynamic, which is the expected model system of development in physiology, biochemistry and molecular biology. It is very important to study about the formation eggs. Vitellogenin gene from Antheraea yamamai. which is mainly compose of yolk protein, was cloned by utilizing to the constructed genomic DNA library of Antheraea yamamai. The mail results were represented as the following: 1 Construction of the AFLP linkage map of silkworm, Bombyx moriAmplified Fragment Length PoKinorphism (AFLP). a novel DNA fingerprinting technique, is10a reliable and powerful approach in detecting polymorphism loci. It has a good applied prospect considering the fact that It has been widely used to construct the linkage map and to locate the gene and the quantitative trait loci (QTL) and so on. At last years it had been applied to the study of silkworm, Bombyx mori.AFLP was applied to construct a linkage map, and Gc was mapped on the linkage map in this research. The following are the detail results:First, 3956 loci were amplified using 28 primer combinations in 44 progenies from a backcross population of C100 and Dazao, but 1018 of loci were polymorphic and 693 of loci were the segregation ratio of 1:1 conforming to Mendel's segregation rules. On average, 36.4 polymorphic loci were amplified by one primer pair.Second, 402 of 694 loci, which include 693 AFLP marker and Gc specific marker, consist of 33 linkage groups. The number of the loci of constructing map is 39.5 percent of that of polymorphic loci and 68 percent of that of the 1:1 segregation ratio. The other included unlinked markers each other an those linkage groups on which contains two markers.Third, 33 linkage groups compose of 25 major linkage groups with 7 to 32 markers and 8 relatively small linkage groups with 3 to 6 markers. The length of the longest linkage group. group2, is 496.1 cent Morgan (cM), while that of the shortest linkage group, group29, is 4.7 cM. The number of the markers on each linkage group varied from 3 to 32, in which group 14 and group33 contains 32 and 3 markers respectively. On average, die distance between two markers is 9.1 cM.Fourth, the total length of 33 linkage groups is 3676.7 cM, and the length of one linkage group is 111.4 cM on average. In this research 33 linkage groups wrere obtained, however silkworm has only 28 chromosomes. It means that some of the linkage groups should be linked together, but we not link them together for the absence of specific markers.Fifth, the marker about Gc, which was located on group 15 of classic linkage map. was mapped between die markers L-P4T6-107 and L-P6T4-84 on group22 in the research.Sixth, there are relatively high clustering markers. The reason could be the markers are too close to have recombination and result from relatively small scale of individuals of BC1 population in the research.This work provides an essential basic for cloning green cocoon gene and improving quickly11green cocoon lines of silkworm. With the molecular markers of linking closely to QTL and green cocoon gene, we can screen die breeding progenies by following the molecular markers and then select the phenotype to improve quickly the green cocoon Line of silkworm. 2 Clone for the Vitellogenin gene from Antheraea yamamaiVitellogenin of Anther aea yamamai is a precursor of major yolk protein synthesized in the female fat body at lar...