The salivary gland chromosomes of Drosophila virilis: a cytological map, pattern of transcription and aspects of chromosome evolution.

By combining information from microscopical observation and photography a graphical map of Drosophila virilis salivary gland chromosomes was constructed. About 1,560 individual bands are shown and patterns of transcription at about 360 sites are indicated. The application of the map is demonstrated by using genetic, morphological and in situ hybridization data to identify the white-Notch regions of D. virilis and Drosophila melanogaster as homologous chromosome segments with constant and variable features.