Abstract
Mixtures of 17-base long oligonucleotides possibly encoding a hexapeptide of Drosophila melanogaster glucose-6-phosphate dehydrogenase were synthesized and used as probes for screening a genomic library of D. melanogaster constructed in Charon 4A vectors. A total of about 60, 000 plaques were initially screened, and after two successive plaque purification three clones carrying the identical 13-kb EcoRI fragment were isolated. That these clones contain the G6PD coding sequence was demonstrated by in situ hybridization of the cloned DNA fragments to salivary gland polytene chromosomes and in vitro translation of the hybrid-selected mRNA. As suggested by Torczynski et al. (1984), this method using short synthetic probes appears versatile for isolating low-copy genes from genomic libraries.
