Abstract
This paper describes a method for the identification of single copy genes in Drosophila melanogaster polytene chromosomes, using fluorescence in situ hybridization (FISH). We demonstrate the detection of white (w), a gene previously mapped to 1‐1.5 region of the linkage map, and to 3C2 region of the cytogenetic map of X chromosome. Squash preparations of polytene chromosomes from salivary glands dissected out from third instar larvae of Drosophila melanogaster were denatured and subjected to hybridization with a digoxigenin labeled probe, corresponding to mini‐white gene. The preparations were then washed and incubated with antidigoxigenin‐fluorescein antibodies. After removal of the nonspecifically bound antibodies, the polytene chromosomes were counterstained with propidium iodide. Fluorescence microscopy revealed white locus in the X chromosome in a subterminal location, in agreement with the above mentioned maps. The protocol is efficient and adaptable for simultaneously multiple signal detection.
Keywords: Drosophila melanogaster, polytene chromosomes, white, FISH, labeled probe, signal detection
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