Identification of Molecular Markers Differentiating Betula papyrifera and B. pumila Populations from Northern Ontario (Canada)

Abstract

Betula is a polyploid and highly polymorphic genus with several species known to hybridize very readily. This high level of introgression has resulted in hybrid populations where different species are sympatric. The main objectives of the present study were to identify putative hybrids between B. papyrifera and B. pumila in the Greater Sudbury Region (Northern Ontario) and to develop ISSR and RAPD markers that can differentiate B. papyrifera and B. pumila and their respective populations. This study revealed extensive introgression of B. papyrifera genes into B. pumila based on morphological characterization in the Greater Sudbury region (Northern Ontario) where these two species coexist. Genomic DNAs were extracted from all the collected genotypes from seven B. papyrifera and five B. pumila populations within the GSR. Additional samples from B. pumila from Wisconsin were also analyzed. All the DNA samples were amplified using ISSR and RAPD primers. No – species – diagnostic markers was identified because in part to a high level of polymorphic loci observed within and among populations. A close look of all the amplified products revealed a number of ISSR and RAPD diagnostic markers that differentiate P. papyrifera populations from different origins. Likewise, diagnostic bands distinguishing B. pumila from Wisconsin to the GSR population were identified.