A comparison of banding patterns in salivary gland chromosomes of two species ofDrosophila

An attempt was made to compare the details of chromosome structure between two distantly related species ofDrosophila, D. melanogaster andD. hydei, which belong to different subgenera. Several short stretches of salivary gland chromosomes were selected on the basis of presumed homologous markers, either mutants associated with chromosome breaks, or experimental puffs. Banding patterns were compared in map diagrams, compiled from photographs. It proved possible to correlate with fair accuracy at least a short sequence of bands in each of the examples studied. The map regions were however very different otherwise. It was not possible to judge in how far this is a consequence of major or very small rearrangements, or other types of change. The chromosomal location of one permanent puff and of several others some of which are formed normally during pupation, and some of which appear after a period of oxygen deprivation, was found to be in complete agreement with genetical data which indicate homology of chromosomes 2 (hydei) with3R (melanogaster), and of 4 with3L. On the other hand, relative position and sequence of these puffs within the chromosome are different in the two species. Supported by the Netherlands Organization for the Advancement of Pure Research, Grant 913-28.