Chromosomal Locations of Microsatellites in Onion

Abstract

Bulb onion ( Allium cepa L.) has a very large genome composed of a high proportion of repetitive DNAs. Genetic analyses of repetitive sequences may reveal microsatellites in order to increase the number of genetic markers in onion. Thirty microsatellites were previously isolated from an onion genomic library (Fischer and Bachmann, 2000). A complete set of Japanese bunching onion ( A. fistulosum ) – shallot ( A. cepa Aggregatum group) monosomic addition lines were used to assign these microsatellites to the chromosomes of A. cepa . Simplified PCR conditions for each microsatellite were determined and 28 of the 30 primer pairs amplified DNA fragments, of which 21 microsatellite markers were assigned to chromosomes of A. cepa . Subsequent mapping of these microsatellites will enable us to establish the chromosomal distribution of these markers.