Origin, diversification, and historical biogeography of the giant kelps genus Macrocystis : Evidences from Bayesian phylogenetic analysis

We evaluate the genetic divergence between the two morphs of the genus Macrocystis found in the Chilean coast (pyrifera and integrifolia), and the historical relationships with the other morphs of the genus using the ITS-2 DNA region sequences. The analyses sustain that the morphotypes, and its distribution, have a strong phylogenetic signal, indicating that historical process associated to the diversification has determined the current distribution and morphological variability. Finally, the pyrifera morph is the most probable ancestor of the actual morphological variability of the genus, which originated in the Northeastern Pacific and later colonized the Southern Pacific.