Details

Autor(en) / Beteiligte

• Napis, S

Titel

Molecular genetic studies on Brassica napus L

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

1991

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The feasibility of using two different methods of assaying for DNA polymorphisms - Restriction fragment length polymorphisms (RFLPs) revealed by a range of characterised Brassica cDNA sequences, and Random amplified polymorphic DNA (RAPD), have been used to reveal DNA polymorphisms between varieties of Brassica napus L.. The sequence and organisation of a Hind III family of highly repetitive DNA sequences were also studied on Brassica napus L. RFLPs associated with rape extensin, ext A, and Brassica oleraceae self-incompabilitity genes were observed when DNA samples from 19 commercial varieties of B.napus were analysed using the cDNA probes pRR566 (coding for root-specific extensin) and pBOS2 (coding for S5 self-incompatibility allele in B.oleraceae). Both cDNA clones were able to reveal RFLP patterns with varying degrees of polymorphism depending on the restriction enzymes used in the digestion of genomic DNAs. Although both probes could generate complex RFLP band patterns, those revealed by pBOS2 were generally easier to analyse and more suitable for DNA fingerprinting while those revealed by pRR566 were less distinct as a result of extensive background hydridisations. The probe pRR566, with certain restriction enzymes generated simpler RFLP band patterns that were more suitable for segregation analyses. Segregation analysis of F1 individuals revealed additive RFLP band pattern of both parental varieties while that of F2 individuals revealed RFLP band patterns of each parental varieties as well as the additive pattern. When analysed for possible association with varietal glucosinolate content, none of the RFLP band patterns showed such linkage. A cDNA library was constructed from pod material of a high glucosinolate variety in an attempt to obtain clones which could reveal RFLP patterns associated with glucosinolate content. Differential screening using total cDNAs from pod materials of high and low glucosinolate varieties failed to isolate any cDNA clones useful as RFLP markers.