Molecular Decay of the Tooth Gene Enamelin (ENAM) Mirrors the Loss of Enamel in the Fossil Record of Placental Mammals

Authors

Robert Meredith, Montclair State UniversityFollow
John Gatesy, Texas A and M University
William J. Murphy, Texas A and M University
Oliver A. Ryder, University of California at Riverside
Mark S. Springer, University of California at Riverside

Document Type

Article

Publication Date

1-1-2009

Journal / Book Title

PLoS Genetics

Abstract

Vestigial structures occur at both the anatomical and molecular levels, but studies documenting the co-occurrence of morphological degeneration in the fossil record and molecular decay in the genome are rare. Here, we use morphology, the fossil record, and phylogenetics to predict the occurrence of "molecular fossils" of the enamelin (ENAM) gene in four different orders of placental mammals (Tubulidentata, Pholidota, Cetacea, Xenarthra) with toothless and/or enamelless taxa. Our results support the "molecular fossil" hypothesis and demonstrate the occurrence of frameshift mutations and/or stop codons in all toothless and enamelless taxa. We then use a novel method based on selection intensity estimates for codons (v) to calculate the timing of iterated enamel loss in the fossil record of aardvarks and pangolins, and further show that the molecular evolutionary history of ENAM predicts the occurrence of enamel in basal representatives of Xenarthra (sloths, anteaters, armadillos) even though frameshift mutations are ubiquitous in ENAM sequences of living xenarthrans. The molecular decay of ENAM parallels the morphological degeneration of enamel in the fossil record of placental mammals and provides manifest evidence for the predictive power of Darwin's theory.

Comments

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

DOI

10.1371/journal.pgen.1000634

Montclair State University Digital Commons Citation

Meredith, Robert; Gatesy, John; Murphy, William J.; Ryder, Oliver A.; and Springer, Mark S., "Molecular Decay of the Tooth Gene Enamelin (ENAM) Mirrors the Loss of Enamel in the Fossil Record of Placental Mammals" (2009). Department of Biology Faculty Scholarship and Creative Works. 365.
https://digitalcommons.montclair.edu/biology-facpubs/365

Published Citation

Meredith, R. W., Gatesy, J., Murphy, W. J., Ryder, O. A., & Springer, M. S. (2009). Molecular decay of the tooth gene Enamelin (ENAM) mirrors the loss of enamel in the fossil record of placental mammals. PLoS genetics, 5(9), e1000634. https://doi.org/10.1371/journal.pgen.1000634