A Widespread Biochemical Polymorphism in Drosophila melanogaster

Abstract

The evidence for the existence of an ebony allele segregating in the Oregon-R stock of D. melanogaster with little or no color effect is given. The allele can be detected by the differential responses of ebony and wild type larvae on food containing phenyl-thio-carbamide (PTC). Additional laboratory stocks polymorphic for ebony alleles were Oregon-K, Kaduna (Nigeria) and Bikini Atoll. A Canton-S stock was found to be homozygous for an ebony allele. Flies collected in the wild at Eugene, Oregon, and in Cambridge, England, in 1961 were polymorphic. Evidence suggests that the polymorphisms are maintained by overdominance of the ebony heterozygote, mating preferences and perhaps other factors. The widespread occurrence of the polymorphism suggests that it is of great importance in maintaining the genetic variability and flexibility of natural populations, especially since few polymorphisms in D. melanogaster have been detected in the past.