RAPD mapping of the pea genome

Includes bibliographical references (pages [70]-71)I have constructed a linkage map of the pea genome based upon classical and molecular-marker traits. Existing morphological, isozyme and RFLP (restriction fragment length polymorphism) markers were supplemented with a powerful new approach called RAPDs, or Randomly Amplified Polymorphic DNAs. The RAPD procedure, developed by Williams et al. (1990) and Welsh and McClelland (1990), involves the amplification of random DNA segments by the arbitrarily primed-polymerase chain reaction (AP-PCR) using single primers of arbitrary nucleotide sequence. Decamer primers consisting of 50%-80% GC content have generated between one and nine DNA products across a range of pea accessions, revealing polymorphism in thirty-nine percent of the samples tested. In each case, the presence of a product was scored as the dominant allele state and its absence in a contrasting individual as the recessive allele state. Over ninety percent of the polymorphisms observed segregated in Mendelian fashion among the F2 progeny of a selected cross in a generally consistent and reproducible manner. A total of 107 polymorphisms (that segregated in Mendelian fashion) were generated. About half of these markers were assigned to positions on an integrated pea nuclear genomic map by linkage association with previously mapped genetic loci.M.S. (Master of Science