Genetic variation in space and time in a population of ponderosa pine

Abstract

The genetic structure of a population of Pinus ponderosa was studied using seven electrophoretically-detectable protein loci. This population is composed of six groups of trees, which differ significantly from each other in their genetic constitutions. The results imply that the population is composed of groups of individuals assembled into genetically-related family units. Whenever such family clusters have been documented in other studies, marked inbreeding has also been noted as a consequence. In this population, no inbreeding is detectable. The groups also differ from one another in several characteristics which have genetic consequences within the population as a whole. These characteristics include age structures, seed output, level of infestation by woolly aphids and extent of damage by deer browsing. The population was also divided into four age classes which do not differ markedly from one another in their genetic characteristics. This suggests that genetic differentiation in time is much less marked than differentiation in space. © 1981 The Genetical Society of Great Britain.