Drosophila can look back at a long tradition,
which provided many useful tools. The studies of heredity in the lab of
Thomas H. Morgan produced a large number of "trick chromosomes":
attached X, balancers (suppressors of recombination), deletions, duplications
and translocations. At those times, the genetic effects of those chromosomes
itself were the subject of interest. Today, these chromosomes are still
a useful tool for any handling with flies.
The beginning of molecular biology opened a new field of Drosophila
research. In 1969 Joseph G. Gall and Mary-Lou Pardue established in
situ hybridization to polytene chromosomes: now genes could be easily
mapped to quite precise locations. Michael Akam developed in situ
hybridization to tissues, to visualize gene expression, in 1983.
In 1982, Gerald M. Rubin and Allan C. Spradling produced the first transgenic
flies, a prerequisite for many follow-up manipulation techniques that
are used today: Enhancer trap, protein trap, induction of gene expression
by exogenous transcription factors (the UAS-Gal4 system), or the use of
site specific recombinases from yeast to induce mitotic clones.