MOLECULAR SIGNATURES OF SELECTION ON REPRODUCTIVE CHARACTER DISPLACEMENT OF FLOWER COLOR IN PHLOX DRUMMONDII
Article first published online: 5 OCT 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 66, Issue 2, pages 469–485, February 2012
How to Cite
Hopkins, R., Levin, D. A. and Rausher, M. D. (2012), MOLECULAR SIGNATURES OF SELECTION ON REPRODUCTIVE CHARACTER DISPLACEMENT OF FLOWER COLOR IN PHLOX DRUMMONDII. Evolution, 66: 469–485. doi: 10.1111/j.1558-5646.2011.01452.x
- Issue published online: 25 JAN 2012
- Article first published online: 5 OCT 2011
- Accepted manuscript online: 26 AUG 2011 05:17PM EST
- Received February 21, 2011, Accepted August 3, 2011, Data Archived: Dryad doi:10.5061/dryad.8792d
- Anthocyanin biosynthesis;
- population structure;
- selective sweep
Character displacement, which arises when species diverge in sympatry to decrease competition for resources or reproductive interference, has been observed in a wide variety of plants and animals. A classic example of reproductive character displacement, presumed to be caused by reinforcing selection, is flower-color variation in the native Texas wildflower Phlox drummondii. Here, we use population genetic analyses to investigate molecular signatures of selection on flower-color variation in this species. First, we quantify patterns of neutral genetic variation across the range of P. drummondii to demonstrate that restricted gene flow and genetic drift cannot explain the pattern of flower-color divergence in this species. There is evidence of extensive gene flow across populations with different flower colors, suggesting selection caused flower-color divergence. Second, analysis of sequence variation in the genes underlying this divergence reveals a signature of a selective sweep in one of the two genes, further indicating selection is responsible for divergence in sympatry. The lack of a signature of selection at the second locus does not necessarily indicate a lack of selection on this locus but instead brings attention to the uncertainty in depending on molecular signatures to identify selection.