Land plant evolutionary timeline: Gene effects are secondary to fossil constraints in relaxed clock estimation of age and substitution rates

• DOI: 10.3732/ajb.1200416
• Publication Date: 2013-02-28T03:45:59Z
• Authors: Susana Magallón; Khidir W. Hilu; Dietmar Quandt
• Keywords: Molecular clock; Gymnosperm; Molecular evolution

Land plants play an essential role in the evolution of terrestrial life. Their time origin and diversification is fundamental to understanding life on land. We investigated timing rate molecular land plants, evaluating effects different types data, including temporal information from fossils, using clock methods. •Ages absolute rates were estimated independently with two substitutionally data sets: a highly conserved 4-gene set matK, fast-evolving gene. The vascular plant backbone crown nodes all major lineages calibrated fossil-derived ages. Dates while or excluding calibrations relaxed clocks that differ their implementation autocorrelation. •Land diverged streptophyte alga 912 (870-962) million years ago (Mya) but diversified into living 475 (471-480) Mya. Ages for land-plant agree fossil record, except angiosperms. Different genes very similar ages correlated across tree. Excluding resulted greatest age differences. provided ages, uncorrelated rates. •Whole-genome accelerations decelerations may underlie genes. suggest pronounced substitution changes around angiosperm node represent challenge model adequately.