Plant & Animal Genome VI Conference

P46

DIVERSITY IN PISUM

Department of Applied Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom

Retrotransposons are one of the major contributors to the generation of genetic diversity in plants with considerable variation in copy number and heterogeneity of primary structure. Here we describe the heterogeneity of PDR1 caused by internal rearrangements, and application of insertion site polymorphisms for assessing the phylogenetic relationships within Pisum. The LTRs of PDR1 are unusually short (156 bp) and show a small amount of sequence heterogeneity. The central part of PDR1 (3613 bp) has been divided into four regions corresponding to functional domains and primer pairs were designed for each domain. PCR was used to assess the pattern of diversity within 16 accessions from the JIC germ plasm collection. All accessions revealed polymorphisms in size of amplification products obtained. Sequencing of these PCR products showed the occurrence of variants involving deletions, inversions, and translocations within PDR1. Each variant makes up a small portion of the PDR1 family but altogether they significantly elevate the overall genetic diversity. 56 Pisum accessions were studied using a novel anchored-PCR based technique, generating 276 markers. This data was used to construct of neighbour joining trees and in principal component analysis. This data set was similar to AFLP data from the same accessions. We have shown that P.abyssinicum does not appear to be a subspecies of P. sativum as previously thought and has probably been domesticated independently.