Paper: A molecular time-scale for eukaryote evolution recalibrated with the continuous microfossil record

Proceedings of the Royal Society B: Biological Sciences
ISSN: 0962-8452 (Paper) 1471-2954 (Online)
Issue: Volume 273, Number 1596 / August 07, 2006

Pages: 1867 - 1872
DOI: 10.1098/rspb.2006.3537

A molecular time-scale for eukaryote evolution recalibrated with the
continuous microfossil record

Cédric Berney and Jan Pawlowski
Department of Zoology and Animal Biology, University of Geneva, Sciences
III, 30, quai Ernest Ansermet, 1211 Geneva 4, Switzerland

Abstract:
Recent attempts to establish a molecular time-scale of eukaryote evolution
failed to provide a congruent view on the timing of the origin and early
diversification of eukaryotes. The major discrepancies in molecular time
estimates are related to questions concerning the calibration of the tree.
To limit these uncertainties, we used here as a source of calibration points
the rich and continuous microfossil record of dinoflagellates, diatoms and
coccolithophorids. We calibrated a small-subunit ribosomal RNA tree of
eukaryotes with four maximum and 22 minimum time constraints. Using these
multiple calibration points in a Bayesian relaxed molecular clock framework,
we inferred that the early radiation of eukaryotes occurred near the
Mesoproterozoic-Neoproterozoic boundary, about 1100 million years ago. Our
results indicate that most Proterozoic fossils of possible eukaryotic origin
cannot be confidently assigned to extant lineages and should therefore not
be used as calibration points in molecular dating.

Abstract and Full Textr Links at The Royals Society
http://tinyurl.com/j5dy3

Posted by
Robert Karl Stonjek


.