Evolution’s
wedges
Finding the genes that drive one species into two
By Daniel Strain
Look to Texas to see evolution’s true colors. There, speckling the state’s green fields, you’ll find the annual phlox, a flower
also known as “Texas pride.” Its pet-
als, a light purple elsewhere, are bright
scarlet in the southeast near Austin. This
color change isn’t a whim: It’s the annual
phlox’s response to the presence of a
close cousin, the pointed phlox. Native
to East Texas, the pointed phlox also has
purplish flowers.
