Interspecific differences revealed with in Drosophila Photometric Analysis

The above refer to experiments present a new method which permits the study of philogenesis in the genus Drosophila. There are several types of results: a) close kinship among the various geographical races of  D. melanogaster in the neo-tropics coincides with their spectrophotometric similarities; b) the interspecific differences are also identified with the photometric analysis; c) finally there are optical density affinities among the various species which belong to the same taxonomic groups.  Acknowledgment. The authors want to express their gratitude to Professor Everet of the physico-chemical laboratory of the National University for the use of his Beckman DU spectrophotometer and for his generous advice. This research is supported by the American Agricultural Research Service grant F. G. Co 107. For technical assistance we are indebted to Miss B. I. Cortés and to Mr. L. Castro.