RAPD Markers For A Mutated Dwarfism Related Site In Brassica Napus And Analysis On Their Seqence Characterized Amplified Regions

A dwarf mutant inbred line DDF-1, approximately 70cm high, was derived from the progeny of a 200cm stemed-high inbred line '3529' (Brassica napus L.) of which seeds were jointly treated with fast neutron and chemical inducer. Genetic analysis of this character revealed that it is under the control of a major mutated gene (dwf1) with additive effect. 50 10-mer RAPD primers were used to identify RAPD (random amplified polymorphic DNA) makers linked to the mutated dwarf locus in B.napus L.. Between two DNA pools of the dwarf and its wild type parent, PCR results of 7 primers showed polymorphisms and all the specific DNA fragments could only be amplified in high parent rather than in the mutant. In the F2 population of the hybrids of the wild type and the mutant, 4 of the 7 markers were identified to be linked to the mutated locus: S5910. S12610. S29390 and S47720 with a map distance of 16.6(cM 0.0(cM) 16.6(cM) and 5.0(cM) respectively. The potential uses of these molecular makers were also discussed.To locate the mutation, we selected two markers with the lowest rates of recombination from the 4 markers. The two markers are nearest to the mutation spot. By using the two markers in the PCR of the backcross B.napus and some other high wild type B.napus, we found the two markers were effective. Sequencing the two markers, we got their sequences and length: S12610 marker is 662bp and S47720 marker is 680bp. By researching the sequences, we built two SCAR (sequence characterized amplified regions) primers. Amplified the sequences with the SCARprimers, but we couldn't get the anticipate results. We guess the dwarf mutant is a spot mutation in the RAPD primer fragment. Using the SCAR primers and the RAPD primers to amplify, we found the mutation locus is in the lower sequence RAPD primers.