Dissection of larval salivary glands and polytene chromosome preparation.

INTRODUCTIONAlthough the large polytene chromosomes of diptera were originally described in the late 1880s, it was not until the early 1930s that their significance to the study of the genome of Drosophila was realized. Polytene chromosomes are found in several larval and adult tissues, but preparations are usually made of the chromosomes in the larval salivary glands, because the glands are easily dissected and the polytene chromosomes are large.