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Allele substitution at a flower colour locus produces a pollinator shift in monkeyflowers


The role of major mutations in adaptive evolution has been debated for more than a century1,2. The classical view is that adaptive mutations are nearly infinite in number with infinitesimally small phenotypic effect3, but recent theory suggests otherwise4. To provide empirical estimates of the magnitude of adaptive mutations in wild plants, we conducted field studies to determine the adaptive value of alternative alleles at a single locus, YELLOW UPPER5,6,7 (YUP). YUP controls the presence or absence of yellow carotenoid pigments in the petals of pink-flowered Mimulus lewisii, which is pollinated by bumblebees5,8,9,10, and its red-flowered sister species11 M. cardinalis, which is pollinated by hummingbirds5,8,9,10. We bred near-isogenic lines (NILs) in which the YUP allele from each species was substituted into the other. M. cardinalis NILs with the M. lewisii YUP allele had dark pink flowers and received 74-fold more bee visits than the wild type, whereas M. lewisii NILs with the M. cardinalis yup allele had yellow-orange flowers and received 68-fold more hummingbird visits than the wild type. These results indicate that an adaptive shift in pollinator preference may be initiated by a single major mutation.

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Figure 1: Near-isogenic lines of M. lewisii and M. cardinalis with alternate alleles at the YUP locus.


  1. Orr, H. A. & Coyne, J. A. The genetics of adaptation: a reassessment. Am. Nat. 140, 725–742 (1992)

    CAS  Article  Google Scholar 

  2. Gillham, N. W. Evolution by jumps: Francis Galton and William Bateson and the mechanism of evolutionary change. Genetics 159, 1383–1392 (2001)

    CAS  PubMed  PubMed Central  Google Scholar 

  3. Fisher, R. A. The Genetical Theory of Natural Selection (Dover, New York, 1958)

    MATH  Google Scholar 

  4. Orr, H. A. The population genetics of adaptation: the distribution of factors fixed during adaptive evolution. Evolution 52, 935–949 (1998)

    Article  Google Scholar 

  5. Hiesey, W. M., Nobs, M. A. & Björkman, O. Experimental Studies on the Nature of Species: V. Biosystematics, Genetics, and Physiological Ecology of the Erythranthe Section of Mimulus 16 (Carnegie Inst. Wash. Publ. 628, Washington DC, 1971)

    Google Scholar 

  6. Bradshaw, H. D. Jr, Wilbert, S. M., Otto, K. G. & Schemske, D. W. Genetic mapping of floral traits associated with reproductive isolation in monkeyflowers (Mimulus). Nature 376, 762–765 (1995)

    ADS  CAS  Article  Google Scholar 

  7. Bradshaw, H. D. Jr, Otto, K. G., Frewen, B. E., McKay, J. K. & Schemske, D. W. Quantitative trait loci affecting differences in floral morphology between two species of monkeyflower (Mimulus). Genetics 149, 367–382 (1998)

    CAS  PubMed  PubMed Central  Google Scholar 

  8. Schemske, D. W. & Bradshaw, H. D. Jr Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus). Proc. Natl Acad. Sci. USA 96, 11910–11915 (1999)

    ADS  CAS  Article  Google Scholar 

  9. Ramsey, J., Bradshaw, H. D. Jr & Schemske, D. W. Components of reproductive isolation between the monkeyflowers Mimulus lewisii and M. cardinalis (Phrymaceae). Evolution 57, 1520–1534 (2003)

    Article  Google Scholar 

  10. Vickery, R. K. Jr Speciation in Mimulus, or, can a simple flower color mutant lead to species divergence? Great Basin Nat. 55, 177–180 (1995)

    Google Scholar 

  11. Beardsley, P. M., Yen, A. & Olmstead, R. G. AFLP phylogeny of Mimulus section Erythranthe and the evolution of hummingbird pollination. Evolution 57, 1397–1410 (2003)

    CAS  Article  Google Scholar 

  12. Mauricio, R. Mapping quantitative trait loci in plants: uses and caveats for evolutionary biology. Nature Rev. Genet. 2, 370–381 (2001)

    CAS  Article  Google Scholar 

  13. Hodges, S. A., Whittall, J. B., Fulton, M. & Yang, J.-Y. Genetics of floral traits influencing reproductive isolation between Aquilegia formosa and Aquilegia pubescens. Am. Nat. 159, S51–S60 (2002)

    Article  Google Scholar 

  14. Grant, V. Historical development of ornithophily in the western North American flora. Proc. Natl Acad. Sci. USA 91, 10407–10411 (1994)

    ADS  CAS  Article  Google Scholar 

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We thank A. Angert, K. Kay, and D. Grosenbacher for field observations of pollinators, P. Beardsley and S. Stefanovic for field assistance, and B. Watson for genotyping. We are grateful to F. Nicholson and the Carnegie Institution of Washington for allowing us to use the Mather field station. Y. Sam provided helpful comments on the manuscript. This work was supported by an award from the National Science Foundation.

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Correspondence to H. D. Bradshaw Jr.

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Bradshaw, H., Schemske, D. Allele substitution at a flower colour locus produces a pollinator shift in monkeyflowers. Nature 426, 176–178 (2003).

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