Construction Of An Oilseed Rape (Brassica Napus .L) Universal Core Genetic Map

Due to many homologous segments or loci within and between A and C genome in amphidiploid Brassica napus, most of the SSR markers developed previously displayed two or more loci, which may brought difficulties in accurate gene mapping. It is hoped to constuct a universal core linkage map of high coverage and more universal. Through analysis of the BAC sequences of Brassica rapa and the GSS sequences of Brassica oleracea, we designed a serial of corresponding SSR markers. A linkage map was constructed using the selected core polymorphic markers and evaluated from many ways. It was found that this map could be featured with high coverage and universal and effectively applied to the integration and comparison of genetic map between different species, gene localization and molecular marker assisted selection in breeding.We developed 2,150 and 3,493 SSR primer pairsfrom the GSS of Brassica oleracea and the BAC sequence of Brassica rapa, which were then designated as BoGMS and BrGMS. A universal core linkage map was constructed using these newly developed SSR markers and a doubled haploid population of Brassica napus. In addition, we analysed the sequence homology between the universal core linkage map of Brassica napus and the linkage map of Arabidopsis thaliana and Brassica rapa by blast search. The main results are as follows:1. We selected 278 markers which were polymorphic between the six Brassica napus lines No.2127-17, ZY821, M201, M202, S1 and S2 from newly designed universal SSR markers and 85 public SSRs as anchored markers, used for constructing a linkage map. Our selection of 151 newly developed BrGMS markers and 136 newly developed BoGMS markers corresponded 287 genetic loci that we were able to map.2. Our linkage map contained 372 marker loci, and coverd 19 linkage group with a Total length 1946.72 cM, and an average interval of 5.23cM between adjacent loci. And 39.64% distorted segregation marker loci weredetected in this map, some of them clustered in some region and distorted to the same parent. 3. We found that 126 (43.90%) BrGMS markers which mapped on A genome of Brassica napus were homologous with the genome sequences of Brassica rapa, of which 114 were mapped to the A genome of Brassica napus.4. Alignment between the 372 SSR of Brassica napus and genome sequences of Arabidopsis thaliana and Brassica rapa by blast,83 of which homology with the genome sequences of Arabidopsis thaliana. The distribution of these markers loci on the Arabidopsis thaliana chromosome were as follows,19 on AtChl (22.9%),14 on AtCh2 (16.9%)%,17 on AtCh3 (20.5%),12 on AtCh4 (14.4%), and 21 on AtCh5 (25.3%).