botanyone
Since the advent of molecular phylogenetics, attempts have been made to infer the evolutionary trajectories of chromosome numbers on DNA phylogenies. Sousa et al.combine cytogenetics, using fluorescent in situ hybridization (FISH), and modelling of changing chromosome numbers in a maximum-likelihood framework to study Typhonium, a genus of Araceae with 2n = 24 and 2n = 8, the lowest known count in the family. A combination of a densely sampled phylogeny, ancestral state modelling and FISH reveals that the species with n = 4 is highly derived, with the FISH data pointing to a Robertsonian fusion-like chromosome rearrangement in the ancestor of this species.
Alex Assiry
