The Comparative Mapping And Comparative Qtl Analysis Between Brassica Napus And Brassica Rapa

The progress in the development of molecular markers and construction of genetic linkage maps make it possible to carry out comparative genomics and comparative QTL (Quantitative Trait Locus) among species. Comparative mapping is one of effective strategies in utilizing genetic information from model plants with completed genomic sequences, such as Arabidopsis thaliana and rice, to their relatives because of its high efficiency on input and output. Meanwhile, comparative QTL analysis could be amplied in different species about the same trait, such as Brasscica species and other relatives of Arabidopsis, by an approach based on a comparative mapping. This approach facilicates the further research on the genetic basement about the complex traits.407 primers including 92 SSR primer pairs and 315 IBP (Intron Based Polymorphism) primer pairs responding to 208 BACs of B.rapa were used for polymorphic assay between the parents of Brassica napus DH population (TNDH) by the partner of our lab. In this study, we do the further assay and select 155 polymorphic primer pairs responding to 155 BACs. And then, 64 IBP markers and 44 SSR primers were mapped onto the TN genetic linkage map which is responding to 104 BACs.After combined other available markers from our lab, a updated TN genetic linkage map was build up with a high density of molecular markers, containing 472 SSR markers, 64 IBP markers, 52 RFLP markers, 91 SNP markers, 57 SRAP markers and 61 SSAP markers. And then, a new Brassica napus consensus map was constructed based on the backbone of TN genetic map after integrated markers from the other public Brassica napus genetic maps such as DY, RNSL genetic linkage map and a consensus genetic linkage map, with a increasing of 119 SSR markers, 19 SNP markers and 31 other markers. At the same time, a new Brassica rapa consensus map was constructed based on the backbone of JWF3P genetic map after integrated markers from the other public Brassica rapa genetic maps such as CK and VCS genetic linkage map containing 658 markers including 439 SSR markers, 145 IBP markers, 48 RFLP markers and 25 CAPS markers.Comparasion of the two consensus maps between A genome was performed, subsequently, based on 10 common markers, 138 common BAC markers between them and 47 pseudo-homologue markers were determined after they were compared with Arabidopsis genomic sequences, respectively. 24 chromosome rearrangements, account for 17.92% of the B.napus A genome, was found between this two divergented genomes, including 20 inversions and 4 indels, but distinct segment insertions/deletions. Glucosinolate content is an important trait for seed quality of Brassica species. A stable conmon QTL which is determining of seed glucosinolate content was detected on A9 linkage group of both TN and CK genetic linkage map under different environments in different years. Comparative QTL indicates the QTL at the same position of B.rapa and B.napus. So we can do some further research about the QTL of glucosinolate content in B. napus using the information of B. rapa.