Allozyme and phenotypic variation in beech (Fagus sylvatica L.): Are there any links?

Abstract

Allozymes are generally considered neutral markers, although there is evidence of adaptive significance of some allozyme markers in many tree species. Nevertheless, as shown by numerous studies, geographical distribution of variation at allozyme loci reflects mainly non-selective processes and phenomena such as colonization, gene flow and founder/bottleneck effects. On the other hand, neutral processes also affect genes controlling quantitative phenotypic traits such as growth and tree architecture. Basic question arising with all gene-marker studies aiming at gene conservation is whether neutral markers can provide any relevant and useful information, i.e. to what extent they reflect variation at genes controlling quantitative and fitness-related traits. This study focuses on potential concordances/discordances in spatial patterns of allozyme and quantitative phenotypic variation. We found that on the range-wide scale, there is no association between phenotypic variation in growth and adaptive traits and neutral allelic richness, but an association with neutral gene diversity. Populations with a high diversity at allozyme loci tend to exhibit also a high intra-population variance of phenotypic traits.