| This thesis investigates the abundance and frequency of microsatellite DNA in barley (Hordeum vulgare L.) genomic database sequences, and demonstrates the versatility and limitation of barley microsatellite-based molecular markers.;Searches of the GenBank and EMBL databases yielded 217 perfect (uninterrupted) microsatellites, consisting of 44 dimeric, 65 trimeric, 73 tetrameric, 22 pentameric and 13 hexameric repeat containing regions. The majority of trimeric and hexameric microsatellites were found in protein coding regions, while all but five of the other microsatellites were located in introns or gene flanking sequences.;Microsatellite polymorphism successfully distinguished the cultivars in a Canadian representative set, using as few as two microsatellite-based primer sets. Twenty-six polymorphic loci were detected across this cultivar set, with two to five alleles found per polymorphic locus. Diversity index values ranged from 0.17--0.76. Correlation was found between allele number and size of dimeric microsatellites, particularly for AG/CT containing repeat regions. Interpretable data from microsatellite loci was equally easy to obtain using DNA extracted from leaf, seed or malt sources. Previously unpublished data and analysis were also reported from collaborative work on a set of six-row cultivars.;The stability of microsatellites over time was examined for 11 and five microsatellites across the pedigrees of the barley lines Harrington and WM872-3, respectively, and nine microsatellites across a set of 15 doubled haploid lines. No new microsatellite allele formation was detected within these lines for the tested microsatellites. During these experiments, within-cultivar microsatellite variation was detected in three cultivars for the compound dimeric microsatellite HVM40 and the perfect GA-containing microsatellite HVM68, thus illustrating the sensitivity of microsatellite markers, and indicating that intravarietal microsatellite variation should be measured before using them as molecular markers.;Nine primers designed to amplify barley AG/CT-containing microsatellites were used successfully to amplify sequences in hexaploid wheat, rye and oat cultivars. Polymorphism was detected across 12 wheat cultivars for two of the nine primer sets, providing preliminary evidence for microsatellite conservation across cereals. |
