Dec 7, 2002

Playing chicken (Gallus gallus): methodological inconsistencies of molecular divergence date estimates due to secondary calibration points

Gene
Shaul Shaul, Dan Graur

Abstract

For any given taxonomic divergence event, one may find in the literature a wide range of time estimates. Many factors contribute to the variation in molecular date estimates for the same evolutionary event. High on the list is the choice of calibration points for converting genetic distances into evolutionary rates and, subsequently, into dates of divergence. In this study, we investigate one critical source of error in estimating divergence times, i.e. the use of secondary calibration points, which are divergence time estimates that have been derived from one molecular dataset on the basis of a primary external calibration point, and which are used again independently of the original external calibration point on a second dataset. Unless particular care is exercised, this practice leads to internal inconsistencies, and the inferred dates of divergence are by necessity unreliable. We present a consistency test for assessing the reliability of divergence time estimates based on secondary calibration points. As a case study, we examine recent estimates of divergence times among phyla and kingdoms based on multiple nuclear protein-coding genes, and show that they fail the consistency test.

  • References9
  • Citations33

References

  • References9
  • Citations33

Citations

Mentioned in this Paper

Nuclear Proteins
Nuclear Protein
Family Dipodidae
Primates
Phyla
Phyla <angiosperm>
Silo (Dataset)
Evolution, Molecular
Amino Acid Substitution
Variation (Genetics)

About this Paper

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