See the GEORGEOUS work done by Hampton Carson in the 60s on
speciation of Drosophila in Hawaiian microenvironments.
Truly georgeous work! You can check his papers or, look at:
Carson, Hampton L.
Chromosome Morphism in Geographically Widespread Species of Drosophila
New York: Academic Press, 1965
Bert Gold, Ph.D.
University of California, San Francisco
School of Medicine
Program in Medical Genetics