A Study on Salivary Gland Chromosomes of Drosophila virilis with a Microphotometer: the sixth chromosome

Abstract

1. The sixth salivary gland chromosomes of Drosophila virilis have been studied with a recording microphotometer.
2. In the graphs recorded by this instrument the chromatic bands and achromatic interspaces are shown as crests and troughs respectively of a wavy curve and the relative staining capacity of the bands is designated by the altitude of the crests.
3. In the sixth salivary chromosome of the Kyoto strain at least eighteen chromosome bands are distinguishable. The same chromosome of the New Orleans strain has a weaker staining capacity. The staining capacities of the chromosomes of these two strains have been estimated quantitatively.
4. A composite chromosome derived from the crossing-over between the Kyoto and New Orleans chromosomes has been studied with the same method.