Spatial genetic structure of allozyme polymorphisms within populations of Pinus Strobus (Pinaceae)

Abstract

The population structure of genetic variation for four allozyme loci was investigated for two populations (one old growth, OG, and the other logged, SS) of eastern white pine (Pinus strobus). Both seedlings and reproductive adults were studied for both study populations. Spatial autocorrelation statistics were used to examine the distribution of allozyme polymorphisms. The spatial genetic structure in adults of population OG indicated that individual genotypes were distributed in a structured, isolation-by-distance manner, consistent with observed levels of pollen and seed dispersal. In contrast, adult genotypes in population SS were nearly randomly distributed, probably as a result of logging. Nonetheless, spatial structuring of genotypes of seedlings occurred at both sites, indicating the power of limited seed flow, as well as temporal Wahlund effects, to create structure. None of four loci in both seedling populations showed a significant departure from Hardy-Weinberg proportions, whereas one and two significant deviations were found for loci in the two respective adult populations. These departures may be attributed to episodic reproductive events.

Spatial Genetic Structure within and among Seed Stands of Pinus engelmannii Carr. and Pinus leiophylla Schiede ex Schltdl. & Cham, in Durango, Mexico

“…leiophylla) at the local level ( Table 2 and Table S1). This matches several previous reports describing that no SGS could be observed in North American stands of conifer species such as Picea chihuahuana, Pseudotsuga menziesii, Pinus strobiformis [13], P. clausa [11], P. strobus [12], P. lumholtzii [6], P. cembroides, P. discolor, P. durangensis, and P. teocote [14]. According to Parker et al [11] and Vekemans and Hardy [1], the main reason for the lack of significant SGS observed in these two pine species at the local level was probably the wind-mediated dispersal mating system, which leads to a strong omnidirectional gene flow.…”

Spatial genetic structure of two sympatric neotropical palms with contrasting life histories

“…For the latter population, Moran's I spatial autocorrelation values were less than 0.01, yet were statistically distinguishable from a random distribution. For the population of C. elatior, mean autocorrelation values for the shortest distances were comparable to I-values of 0.075 for Psychotria nervosa (Dewey and Heywood, 1988), B0.05 for Quercus laevis (Berg and Hamrick, 1995) and 0.05 for an old growth population of Pinus strobus (Epperson and Chung, 2001). Weak spatial structure at the C. elatior (I u ¼ 0.034, I w ¼ 0.039) and C. tepejilote (I u ¼ 0.008, I w ¼ 0.009) populations is in broad terms consistent with those of some predominantly outcrossing, woody perennial plant species reported previously.…”

Genetic Structure of Age Classes in Camellia Japonica (Theaceae)

“…f ij has been used in a number of recent studies (e.g., Loiselle et al 1995 Kalisz et al 2001;Parker et al 2001;Chung et al 2002;Chung et al 2003). Values of I-statistics averaged over alleles allowed indirect estimation of Wright's (1943) neighborhood size (Epperson and Li 1996;Epperson et al 1999;Chung and Epperson 1999;Epperson and Chung 2001). For Moran's I-statistics, only one allele was considered at diallelic loci, because in this case the second allele contributes identical information.…”