Wildflower Colors Tell Butterflies to Prevent Sterile Offsprings

Time and separation are two major factors to restrict gene flow and to evolve a new species. However, in Texas wildflowers, a gene for color-coding prevents formation of new species as discovered by Robin Hopkins, a graduate student from Duke University.

Wildflowers with periwinkle blue blossom are called Phlox drummondii, while Phlox cuspidata have light blue petals. Both have blue flowers however, P. drummondii are darker and some are almost red in color. Since butterflies have color preferences, some land only on blue flowers, some on red, thus cross between the two species is prevented. Because when this happens, the cross would produce an offspring that is nearly sterile, causing the next generation to be a genetic dead end. This phenomenon of preventing "two similar proto-species moving apart by discouraging hybrid mating" is called reinforcement.

"There are big questions about evolution that are addressed by flower color," said Hopkins, who successfully defended her doctoral dissertation just weeks before its publication in Nature journal.

Read the original article at http://www.dukenews.duke.edu/2011/01/texasflowers.html. Subscribers of the Nature journal can access the research article at http://www.nature.com/nature/journal/vaop/ncurrent/full/nature09641.html.