Reconstruction of ancestral genome size in Pitcairnioideae (Bromeliaceae) : what can genome size tell us about the evolutionary history of its five genera?

Abstract

We expand the genome size (GS) database for Bromeliaceae, specifically for subfamily Pitcairnioideae, and verify whether GS can provide information on the diversification of the five genera in this subfamily. We also provide a phylogenetic perspective on GS evolution in the subfamily and reconstruct the ancestral state for this character. We show that the evolutionary path of GS from the origin of angiosperms to the origin of Pitcairnioideae agrees with the proportional model of GS evolution. Furthermore, we propose that the high phenotypic diversity that is found across Bromeliaceae and that is well represented in Pitcairnioideae is both correlated with high rates of GS evolution of the species and associated with a short period of diversification. The paper also highlights the value of flow cytometry as a rapid and reliable technique for generating GS data which can be analysed in conjunction with other molecular and morphological data to help elucidate patterns of evolution and phylogenetic relationships within this family.