PARENT SESSION
Poster Session #48: Population Genetics.
Friday, August 10, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
81
Fine scale genetic and spatial analysis of old growth eastern white pine (Pinus strobus).
Marquardt, Paula1,2, Epperson, Bryan1, 1 2
ABSTRACT- Natural populations of tree species are dynamic systems. Stand age, population density, and dispersal distances of pollen and seed interrelate with spatial ecological processes such as mating system, natural selection and genetic drift. These interacting spatial factors determine the genetic diversity and genetic structure for a population. Diversity, spatial structure, and population structure of two populations of Pinus strobus were determined by simple sequence repeat (SSR) marker analysis. We evaluated old growth and second growth populations, located within Hartwick Pines State Park, Grayling, Michigan. The second growth population was harvested in the late 1800's and regenerated naturally. From each population, approximately 120 contiguous trees were genotyped at eight repetitive loci. The old growth stand captured 88% of the diversity contained in both populations, with the second growth stand maintaining a higher percentage of overall alleles at 95%. The second growth stand also maintained more unique alleles at 12% compared to 5% for the old growth stand. Moran's I analysis suggests a randomly distributed second growth population versus weak positive spatial structure at short distances for the old growth population. We hypothesize that logging decreased spatial structure at the second growth site. These measures indicate that changes in spatial structure of a stand can alter levels of genetic diversity, potentially affecting the stand's ability to respond to environmental changes.
KEY WORDS: Pinus strobus, population genetics, spatial structure, simple sequence repeats