Molecular and cytological analyses of Deschampsia cespitosa populations from Northern Ontario (Canada)

Deschampsia cespitosa is widely dispersed around the globe, particularly in the northern hemisphere. A high tolerance to adverse environmental conditi ons allows D. cespitosa to colonize and dominate plots of land that are uni nhabitable by other plants. The main objective of the present study was to determine the degree of genetic variation and relatedness among D. cespitos a populations from heavy metal contaminated sites and uncontaminated sites in Northern Ontario, using RAPD markers. Genomic DNA samples from individua l plants were analyzed using 35 oligonucleotides of random sequence. Twenty -eight of these primers allowed amplification of random polymorphic DNA (RA PD) loci. Overall, 90% of RAPD bands were polymorphic. Analysis of molecula r variance revealed that 72% of the variation could be attributed to indivi dual differences within each of the populations. The within- and among-regi on variations accounted for 14 and 15% of the total molecular variance, res pectively. Population-specific RAPD markers were identified. RAPD markers s pecific to D. cespitosa were isolated, cloned, and characterized. Cytogenet ic analysis revealed a high level of aneuploidy in all the populations from Northern Ontario, with chromosome numbers varying from 2n = 18 to 2n = 26.