• Corpus ID: 85928175

Calibrating and constraining molecular clocks

@inproceedings{Benton2009CalibratingAC,
  title={Calibrating and constraining molecular clocks},
  author={Michael J. Benton and Philip C. J. Donoghue and Robert J. Asher},
  year={2009}
}

• M. Benton, P. Donoghue, R. Asher
• Published 2009
• Biology

In dating phylogenetic trees, it is important to work to the strengths of paleontology and molecular phylogeny estimation. Minimum constraints on calibrations (i.e., oldest fossils in a crown clade) may be calculated with some precision and may be treated as hard bounds, while maximum constraints are soft bounds that may be represented most honestly by probability distributions that refl ect the distribution of fossiliferous rocks around the time in question, but allow a small probability of truly ancient dates as well. We present deta iled documenta tion of 63 key ca libra tion dates, with thorough evidence and error expressions, for a wide range of organisms. For well over 200 years, natural scientists have used fossils with varying degrees of conA dence to date the evolution of life. 7 e A eld has advanced dramatically in the last few years, and it would be useful now to review some of the key issu es and to su ggest an ou tline of a modus operandi for the future. In explaining the role of fossils in establishing timescales,t is us efu l to review the historical sequ ence in which key observations were made. Much of this early history predates the 1960s conceptfhe molecu lar clock; but the way in which fossils should be used today depends crucially on those earlier geological and paleontological observations. In presenting these observations in a logical sequence, we highlight what can and cannot be done with fossils, and link this to the relative strengths and weaknesses of molecular data. 7 e value of carrying out this survey now is that it is not framed in the old and rather worn narrative of a “conP ict” between fossils and