Continuously Growing Rodent Molars Result from a Predictable Quantitative Evolutionary Change over 50 Million Years

Vagan Tapaltsyan, Jussi T. Eronen, A. Michelle Lawing, Amnon Sharir, Christine Janis, Jukka Jernvall*, Ophir D. Klein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The fossil record is widely informative about evolution, but fossils are not systematically used to study the evolution of stem-cell-driven renewal. Here, we examined evolution of the continuous growth (hypselodonty) of rodent molar teeth, which is fuelled by the presence of dental stem cells. We studied occurrences of 3,500 North American rodent fossils, ranging from 50 million years ago (mya) to 2 mya. We examined changes in molar height to determine whether evolution of hypselodonty shows distinct patterns in the fossil record, and we found that hypselodont taxa emerged through intermediate forms of increasing crown height. Next, we designed a Markov simulation model, which replicated molar height increases throughout the Cenozoic and, moreover, evolution of hypselodonty. Thus, by extension, the retention of the adult stem cell niche appears to be a predictable quantitative rather than a stochastic qualitative process. Our analyses predict that hypselodonty will eventually become the dominant phenotype.

Original languageAmerican English
Pages (from-to)673-680
Number of pages8
JournalCell Reports
Issue number5
StatePublished - 2015
Externally publishedYes

Bibliographical note

Funding Information:
We thank Jan Schnitzler, Jan Prochazka, Jimmy Hu, Kenneth Locey, and Mikael Fortelius for comments and assistance. This work was funded by the NIH through the NIH Director’s New Innovator Award Program, DP2-OD007191, and by R01-DE021420, both to O.D.K; by F30-DE022482 to V.T.; F32-DE023702 to A.S.; a Marie Curie fellowship to J.T.E., and the Academy of Finland to J.J.

Publisher Copyright:
© 2015 The Authors.


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