Genetic Architecture in Bur Oak, Quercus macrocarpa (Fagaceae), Inferred by Means of Spatial Sutocorrelation Analysis

Berlin

1994

S. 63-74

35 Lit. Ang.

Serie

8971S

400084976

Allozyme variation at seven putative polymorphic gene loci (Fle, Idh, Mdh-2, Mdh-3, 6 Pgd-2, Pgi-2, Pgm) was quantified in an isolated Quercus macrocarpa population in northwestern Ontario, Canada. The bur oaks studied were slightly less genetically variable (He = 0.196, A = 3.43) than the Quercus subg. Lepidobalanus average. To assess the genetic differentiation within the topodeme, MORAN'S spatial autocorrelation coefficients were used for the nearest-neighbor map and correlograms. Results indicate that most alleles were randomly distributed in space. However, significant genetic patches were detected for two Fle-alleles. Patch width was inferred to be less than 10m. This spatial substructure may be due to limited gene flow and/or demographic factors. Spatially varying selection can be probably excluded as a spatial evolutionary force, since site conditions were very homogeneous.