ISOLATION, CHARACTERIZATION AND MAPPING OF SIMPLE SEQUENCE REPEAT LOCI IN POTATO

Solanum tuberosum L. DNA sequences containing simple sequence repeat ( SSR) motifs were extracted from the EMBL database, cDNA and selectivel y enriched small-insert DNA libraries. Enrichment was achieved using e ither tripler affinity capture or single-strand hybridisation selectio n. One hundred and twelve primer pairs which successfully amplified pr oducts of the correct size from potato DNA were ultimately designed an d synthesised. Ninety-eight of these revealed length polymorphisms in a panel of four diploid and two tetraploid clones, in agreement with t he high information content of this class of markers which has been fo und in other species. All of the markers were assigned a quality score of 1-5 based on their potential usefulness. Eighty-nine loci from 65 of the primer pairs were located on two genetic linkage maps of potato by segregation analysis of the amplified alleles. Fifty-two of the SS Rs were clearly single locus. The maps were aligned using 23 SSR prime r pairs and 13 RFLP loci mapped in both populations. The markers descr ibed constitute a class which should replace Restriction Fragment Leng th Polymorphisms (RFLP) as the markers of choice for future genetic st udies in potato. The sequences of the primers, together with other inf ormation on these markers are provided.