The use of chloroplast DNA polymorphism in studies of gene flow in plants.

In many species of plants, the dispersal of genes is mediated by the movement of both seeds and pollen. The relative contributions of seed and pollen movement to total gene flow can be difficult to estimate. Chloroplast DNA (cpDNA) may prove useful for resolving this problem. Over the past several years, studies of numerous species of plants have shown that intraspecific variation in cpDNA is often sufficiently abundant to serve as a marker for studies of gene flow. Recent theoretical models have shown that estimates of population structure based on cpDNA polymorphism should be especially sensitive to the impact of seed movement on gene flow, because cpDNA is often maternally inherited.