GENETIC-MARKERS IN PLANT EVOLUTIONARY ECOLOGY

Genetic markers have provided plant ecologists with a method of assess ing levels of genetic relatedness among individuals and populations. I n recent years a number of techniques based on DNA sequence variation have been developed to complement allozyme methods that are already wi dely used. Some of these new markers are more variable than protein-ba sed markers, allowing more precise estimates of genetic differences am ong individuals and populations. Other DNA-based markers are based on organelle genomes that are inherited uniparentally. These cytoplasmic markers can provide a method for assessing the separate effects of see d and pollen dispersal on gene flow within and among populations and s pecies. Studies of hybrid populations have been facilitated by the dev elopment of inferential techniques for assessing levels of selection a nd patterns of introgression between species. Genetic markers have als o been used to describe mating patterns within populations and to exam ine the ecological and genetic mechanisms that contribute to variation in selfing and reproductive success. Integration of ecological method s with genetic marker techniques continues to provide novel approaches to the study of evolutionary processes in plant populations.