Genetic markers: tools for identifying and characterising scots pine populations

Abstract

Genetic diversity is the basis for ecological biodiversity; it can only be assessed by using markers which reflect the variation present within the genome. Biochemical plant constituents interact with other components of the ecosystem and are thus of greater value as adaptive markers than as truly genotypic characters; however, the terpene components of coniferous resin systems are under strong genetic control and are valuable population diversity indicators. Molecular markers are impervious to environmental modification and therefore represent the genotype most faithfully. A survey is presented of the applications of the major biochemical and molecular marker systems in the analysis of Scots pine populations, together with indications of the advantages and limitations of each category of marker. The unusually high phenotypic diversity evident within the species at the morphological and physiological levels, both within populations and between geographical regions, is further substantiated by the degree of genotypic diversity evident from biochemical and molecular analysis. Molecular markers currently available mostly measure selectively neutral variation; among the most important needs for the future is the development of molecular markers for adaptive traits.