A multi-locus time-calibrated phylogeny of the brown algae (Heterokonta, Ochrophyta, Phaeophyceae): Investigating the evolutionary nature of the "brown algal crown radiation"

作者：Silberfeld Thomas^*; Leigh Jessica W; Verbruggen Heroen; Cruaud Corinne; de Reviers Bruno; Rousseau Florence

来源：Molecular Phylogenetics and Evolution, 2010, 56(2): 659-674.

DOI：10.1016/j.ympev.2010.04.020

• Phaeophyceae
• Brown algal crown radiation
• Multi-marker phylogeny
• Time-calibrated phylogeny
• Bayesian relaxed molecular clock
• Hard/soft polytomy
• Non-molecular characters evolution

The most conspicuous feature in previous phaeophycean phylogenies is a large polytomy known as the brown algal crown radiation (BACR). The BACR encompasses 10 out of the 17 currently recognized brown algal orders. A recent study has been able to resolve a few nodes of the BACR, suggesting that it may be a soft polytomy caused by a lack of signal in molecular markers. The present work aims to refine relationships within the BACR and investigate the nature and timeframe of the diversification in question using a dual approach. A multi-marker phylogeny of the brown algae was built from 10 mitochondria!, plastid and nuclear loci (>10,000 nt) of 72 phaeophycean taxa, resulting in trees with well-resolved inter-ordinal relationships within the BACR. Using Bayesian relaxed molecular clock analysis, it is shown that the BACR is likely to represent a gradual diversification spanning most of the Lower Cretaceous rather than a sudden radiation. Non-molecular characters classically used in ordinal delimitation were mapped on the molecular topology to study their evolutionary history.

• 出版日期2010-8