Inferring hypothesis-based transitions in clade-specific models of chromosome number evolution in sedges (Cyperaceae)

Publication date: Available online 15 March 2019Source: Molecular Phylogenetics and EvolutionAuthor(s): José Ignacio Márquez-Corro, Santiago Martín-Bravo, Daniel Spalink, Modesto Luceño, Marcial EscuderoAbstractLarge-scale changes in chromosome number have been associated with diversification rate shifts in many lineages of plants. For instance, several ancient rounds of polyploidization events have been inferred to promote genomic differentiation and/or isolation and, consequently, angiosperm diversification. Dysploidy, although less studied, has been suggested to also play an important role in angiosperm diversification. In this article, we aim to elucidate the role of chromosomal rearrangements on lineage diversification by analyzing a new comprehensive sedge (Cyperaceae) phylogenetic tree. Our null hypothesis is that the mode and tempo of chromosome evolution is to be homogeneous across the complete phylogeny. In order to discern patterns of diversification shifts and chromosome number changes within the family tree, we tested clade-specific chromosome evolution models for several subtrees according to previously reported increments of diversification rates. Results show that a complex, heterogeneous model composed of different clade-specific chromosome evolution transitions are significantly supported against the null hypothesis of a model with no chromosome number model transition events along the phylogeny. This could suggest a link between diversification and chan...
Source: Molecular Phylogenetics and Evolution - Category: Molecular Biology Source Type: research