Spatial patterns of genetic variation: Old growth white pine.

摘要

Natural populations of tree species are dynamic systems: population demographics such as age, density and dispersal distance interact with evolutionary processes to determine spatial genetic structure. Old growth and second growth populations were evaluated, located within Hartwick Pines State Park, Grayling, MI. From each population, 120--122 contiguous trees were sampled for genetic analysis at seven SSR (simple sequence repeat) DNA loci. Genetic diversity was high and inbreeding levels were low for both populations. There was little divergence in allele frequency between populations. Spatial autocorrelation analysis suggested that individual genotypes were randomly distributed in the second growth population whereas weak positive spatial structure was observed at short distances for individuals in the old growth population. Logging may have decreased the degree of spatial structuring at the second growth site, suggesting that silvicultural practices may alter "natural" spatial patterns. Spatial structure is the main factor increasing levels of biparental inbreeding.