Multivariate analysis of allozymic and quantitative trait variation in Alnus rubra: geographic patterns and evolutionary implications

Abstract

Frequency data from six polymorphic allozyme loci and measurements of six quantitative traits were used to examine geographic differentiation among 65 British Columbia provenances of red alder (Alnus rubra Bong.). Principal components analysis showed that variation in quantitative traits can be reduced to two underlying dimensions, one representing general vigor including the termination of the growing period and the other being the start of the growing period. Canonical correlation analysis among quantitative traits, allozyme frequencies, and geographic variables revealed complex associations of quantitative traits with the latitude, distance to the coast, and elevation of the seed source. There were no significant correlations among allozyme frequencies and quantitative traits, but the frequency of the most common allele at most loci decreased with latitude. Further, cluster analysis based on Nei's genetic distance revealed a strong differentiation among island and mainland provenances at one allozyme locus. This differentiation can be interpreted as a result of migration from two different refugia since the last glaciation. The island populations presumably originate solely from isolated coastal refugia west of the Cordilleran ice sheet, while mainland populations were also recruited from areas south of the ice.

What can nuclear microsatellites tell us about maritime pine genetic resources conservation and provenance certification strategies?

“…A slight concordance of morphological and allozymic variation has also been reported for other forest species with wide ranges (e.g. Pseudotsuga menziesii [8]; Picea abies [16]; Alnus rubra [12]). …”

Genetic diversity of central and peripheral populations of Toona ciliata var. pubescens, an endangered tree species endemic to China

“…Some researchers believe that migration from central populations can partly compensate for low density and reproductive success rates, thereby maintaining relatively high genetic diversity in peripheral populations (Kirkpatrick and Ravigne, 2002;Hampe and Petit, 2005). Hamann et al (1998) and Gapare et al (2005) conducted studies on Picea sitchensis (Bong.) Carr and Alnus rubra (Bong), respectively, and showed that because of high levels of gene flow between populations, their peripheral and central populations have high levels of genetic diversity.…”

Genetic diversity estimates of Pinus pinaster in the Iberian Peninsula: a comparison of allozymes and quantitative traits

“…A slight concordance of morphological and allozymic variation has also been reported for other forest species with wide ranges [e.g., Pseudotsuga menziesii (Mirb.) Franco, El-Kassaby, 1982; Picea abies K., Lagerkrantz and Ryman, 1990; and Alnus rubra Bong., Hamann et al, 1998]. It has been suggested that environmental gradients, as measured by geographic variables, may have selective effects on quantitative traits as well as influences on effective population size, explaining the weak correlation usually found among allozyme loci and quantitative traits (Hamann et al, 1998).…”

“…Franco, El-Kassaby, 1982; Picea abies K., Lagerkrantz and Ryman, 1990; and Alnus rubra Bong., Hamann et al, 1998]. It has been suggested that environmental gradients, as measured by geographic variables, may have selective effects on quantitative traits as well as influences on effective population size, explaining the weak correlation usually found among allozyme loci and quantitative traits (Hamann et al, 1998). This last explanation seems plausible in maritime pine as a gradient in climatic conditions is present from south to north of the Iberian Peninsula.…”

“…However, molecular marker data are generally weakly correlated with adaptive variation (Lynch, 1995;Hamann et al, 1998). The correlation between estimates of genetic diversity derived using neutral molecular markers and quantitative traits is usually poor, which limits the value of molecular data in conservation decision-making.…”