Construction And Analysis Of The Linkage Map Of Silkworm, Bombyx Moriusing AFLP Molecular Marker

The silkworm, Bombyx mori., one of the important economic insects and an ideal model organism for biology study, plays an important role in our country. Constructing the linkage map of silkworm, Bombyx Mori., will lead to much great progress of molecular biology of Bombyx mori. Furthermore.it is also an important bridge between basic and applied research in silkworm. It can carry out the analysis and location of QTLs for quality or resistance to diseases.lt may make an efficient breeding possible through the selection of molecular markers,and it may also carry out the research of cloning genes and introduction of foreign genes. As a result,we set up the methods of RAPD, SADF> AFLPand constructed their maps. Based on this, What we carried out in the research is to construct a linkage map with a high density that can be used to map the QTL and to lay the foundation of MAS.Amplified Fragment Length Polymorphism, i.e. AFLP, is a novel molecular marker technique, having both the high polymorphism of RAPD and the reliability of RFLP. It has a good applied prospect considering the fact that it has been used to construct the linkage map and to map the quantitative trait locus(QTL) widely.AFLP was used to construct a dense linkage map of Bombyx mori. in the paper. The following are the results: 1. Improve on AFLP-silver straining(1) From various test we improve on silver stainingrsmearing with segregate-silane on the face of short glass and dealing with 100% ethanol on glass could obviously avoid the split of gel. In addition ,this study explore how to avoid the bubble.(2) In this study.temperature was found to influence the silver straining AFLP molecular markers in3silkworm.The optimum temperature for the preparation of the glass and the gel appeared to be approximately 25℃.2. Text of Polymorphism for AFLP markersTotal 1559 polymorphic loci were amplified using 66 primer combinations. On average, 23.6 polymorphic bands are amplified by one primer combination.Throug the test of Che-square(X2) ,692 showed the segregation ratio of 3:1 in the 1559 polymorphic loci .The detected fragments are from lOObp to lOOObp.3. Text of inheritance pattern for AFLP markersAccording to the text of inheritance pattern for AFLP markers, AFLP was a powerful N sensitive and tapid technique which permitted inspection of polymorphism at a large number of loci within a short period of time. All the AFLP markers examined appeared to display dominant segregation patterns as RAPD.4. Construction the Molecular Linkage Map of the Silkworm(1) "a", "b" subgroup were constructed using 550 polymorphic loci, which was part of the 692 efficient polymorphic loci. The other doesn't link each other by our calculation and can't be used to construct the linkage map. The 550 loci account about 79.48% of the 692 efficient loci and 35.28% of the total polymorphic loci.(2) The 302 markers from Xiang hui were sorted into 21 linkage groups .named as "a" subgroup which included 233 linkage loci and 69 non-linkage loci. The 390 markers from 872 were sorted into 28 linkage groups.named as "b" subgroup which included 317 linkage loci and 73 non-linkage loci.(3) "a" subgroup was composed of 4-43 makers with lenth ranging of 22.3 cM-424.3cM and a mean of 3.98cM-17.43cM which the average length was 8.81cM. Of the 21 linkage groups,13 has an average distance less than 10cM,and 8 is no less than 10cM and no more than 20cM .In 21 linkage groups,there were 11.1 loci on average with a mean length of 89cM. "b" subgroup was composed of 3-35 makers with length ranging of 2.4 cM-366.5cM and a mean of 0.8cM-26.96cM which the average length was 9.26 cM. Of the 28 linkage groups, 18 has an average distance less than 10cM,and 10 is no less than lOcM and no more than 20cM. In 28 linkage groups,there were 11.3 loci on average with a mean length of 95.6cM.(4) The total map distance were 1868.1cM in "a" subgroup and 2677.50cM in "b" subgroup.The total average map distance between "a" subgroup and "b" subgroup was 2272.8cM .(5) The re...