Out of pollen" hypothesis for origin of new genes in flowering plants: Study from arabidopsis thaliana

Abstract

New genes, which providematerial for evolutionary innovation, have been extensively studied formany years in animals where it is observed that theycommonly showan expression bias for the testis. Thus, the testis is amajor source for the generation of newgenes in animals. The source tissue for new genes in plants is unclear. Here, we find that new genes in plants show a bias in expression to mature pollen, and are also enriched in a gene coexpression module that correlates with mature pollen in Arabidopsis thaliana. Transposable elements are significantly enriched in the new genes, and the high activity of transposable elements in the vegetative nucleus, compared with the germ cells, suggests that new genes are most easily generated in the vegetative nucleus in the mature pollen. We propose an "out of pollen" hypothesis for the origin of new genes in flowering plants.