Two genetic changes in cis-regulatory elements caused evolution of petal spot position in Clarkia


A major premise in evolutionary developmental biology is that regulatory changes, often involving cis-regulatory elements, are responsible for much morphological evolution. This premise is supported by recent investigations of animal development, but information is just beginning to accumulate regarding whether it also applies to the evolution of plant morphology1,2,3,4. Here, we identify the genetic differences between species in the genus Clarkia that are responsible for evolutionary change in an ecologically important element of floral colour patterns: spot position. The evolutionary shift in spot position was due to two simple genetic changes that resulted in the appearance of a transcription factor binding site mutation in the R2R3 Myb gene that changes spot formation. These genetic changes caused R2R3 Myb to be activated by a different transcription factor that is expressed in a different position in the petal. These results suggest that the regulatory rewiring paradigm is as applicable to plants as it is to animals, and support the hypothesis that cis-regulatory changes may often play a role in plant morphological evolution.

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Fig. 1: Photographs of Clarkia flowers.
Fig. 2: Hypothesized molecular mechanism of shift in petal spot position.
Fig. 3
Fig. 4: Function of CgbHLH1 and CgCPC1 in C. gracilis petals.

Change history

  • 26 June 2020

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.


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We thank T. Martins, S. Zebell, C. Wilson and R. Zentella for technical advice. We thank X. Dong and F. Nijhout for comments on the manuscript. Photographs are by M. Below, K. Morse, V. Smith and B. Breckling. This work was supported by a National Science Foundation grant to M.D.R.

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P.J. and M.D.R. designed the project; P.J. performed the experiments and the analyses; P.J. and M.D.R. wrote the paper.

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Correspondence to Peng Jiang.

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Jiang, P., Rausher, M. Two genetic changes in cis-regulatory elements caused evolution of petal spot position in Clarkia. Nature Plants 4, 14–22 (2018).

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