Genetic divergence and geographical speciation in Layia ( Compositae).

Abstract

Electrophoretic variability was examined in 6 species of Layia native to California, and regarded as a classic example of geographic speciation, to test the hypothesis that the extent of divergence in structural genes coding enzymes is concordant with divergence in morphological characteritics, ecological traits, and reproductive isolation. Eleven enzymes specified by 17 loci were analyzed. Genetic identity values were consistent with those expected on the model that the species diverged gradually as they adapted to geographically separate habitats. Results provide an important contrast to the very high genetic identifies between species which originated rapidly from their progenitors. -from Authors