Congruence of Morphological and Molecular Phylogenies
- 547 Downloads
When phylogenetic trees constructed from morphological and molecular evidence disagree (i.e. are incongruent) it has been suggested that the differences are spurious or that the molecular results should be preferred a priori. Comparing trees can increase confidence (congruence), or demonstrate that at least one tree is incorrect (incongruence). Statistical analyses of 181 molecular and 49 morphological trees shows that incongruence is greater between than within the morphological and molecular partitions, and this difference is significant for the molecular partition. Because the level of incongruence between a pair of trees gives a minimum bound on how much error is present in the two trees, our results indicate that the level of error may be underestimated by congruence within partitions. Thus comparisons between morphological and molecular trees are particularly useful for detecting this incongruence (spurious or otherwise). Molecular trees have higher average congruence than morphological trees, but the difference is not significant, and both within- and between-partition incongruence is much lower than expected by chance alone. Our results suggest that both molecular and morphological trees are, in general, useful approximations of a common underlying phylogeny and thus, when molecules and morphology clash, molecular phylogenies should not be considered more reliable a priori.
KeywordsCongruence Morphology Molecules Phylogenetic accuracy Tree distance metrics
This work was partially funded by a Leverhulme Trust grant to MJB, and by a BBSRC grant 40/G18385, and an NHM-MRF award to MW. DP was supported by a Marie Curie Intra European Individual Fellowship (MEIF-CT-2005-010022). We would like to thank Anthony Bledsoe, Andy Purvis and Clive Moncrieff for the useful advice on statistical data analyses, and Richard Olmstead and two anonymous reviewers for their helpful and insightful comments.
- Day WHE (1983) Distribution of distances between pairs of classifications. In: Felsenstein J (ed) Numerical taxonomy. NATO ASI Series, vol G1. Springer-Verlag, Berlin, pp 127–131Google Scholar
- Hillis DM, Wiens JJ (2000) Molecules versus morphology in systematics: conflicts, artefacts, and misconceptions. In: Wiens JJ (ed) Phylogenetic analysis of morphological data. Smithsonian Institution Press, Washington, pp 1–19Google Scholar
- Lee MSY (1995) Historical burden in systematics and the interrelationships of ‘parareptiles’. Biol Rev 70:459–547Google Scholar
- Page RDM (1997) Component lite v.0.1. Department of Zoology, University of GlasgowGoogle Scholar
- Penny D, Hendy MD, Steel MA (1991) Testing the theory of descent. In: Miyamoto MM, Cracraft J (eds) Phylogenetic analysis of DNA sequences. Oxford University Press, New York, pp 155–183Google Scholar
- Pisani D (2002) Comparing and combining data and trees in phylogenetic analysis. Ph.D. Thesis. Department of Earth Sciences, University of BristolGoogle Scholar
- Scotland RW, Olmstead RG, Bennett JR (2003) Phylogeny reconstruction: the role of morphology. Syst Biol 52:539–548Google Scholar
- Siegel S, Castellan NJ Jr (1989) Nonparametric statistics for the behavioral sciences. McGraw-Hill, New YorkGoogle Scholar
- Sokal RR, Rohlf FJ (1995) Biometry: the principles and practice of statistics in biological research, 3rd edn. W.H. Freeman and Company, New YorkGoogle Scholar
- Swofford DL, Olsen GJ, Waddell PJ, Hillis DM (1996) Phylogenetic inference. In: Hillis DM, Moritz C, Mable BK (eds) Molecular systematics. Sinauer, Sunderland, pp 407–514Google Scholar
- Thorley JL, Wilkinson M, Charleston M (1998) The information content of consensus trees. In: Rizzi A, Vichi M, Bock HH (eds) Advances in data science and classification. Springer-Verlag, Berlin, pp 91–98Google Scholar