STRATEGY FOR CHROMOSOMAL ASSIGNMENT OF EXPRESSED SEQUENCES DERIVED FROM HETERONUCLEAR RNA

The chromosomal localization of transcribed sequences/genes is one of the objectives of the human genome project. Here, we describe a novel strategy for fast and dependable chromosomal assignment of expressed s equences that contain Alu sequences. Alu-PCR was performed on cDNA tha t was derived from heteronuclear (hn) RNA. hn-cDNA libraries are utili zed for the identification of genes from extended human chromosomal re gions or entire chromosomes. For chromosomal assignment, Alu-PCR produ cts larger than 500 bp were hybridized against genomic DNA of somatic cell hybrids that was also amplified by Alu-PCR. Hybridization signals obtained within 2-3 h of exposure allow localization of cDNA-derived Alu-PCR products to single chromosomes. This technique is particularly useful for the analysis of cDNA libraries derived from hn-RNA. Using hn-cDNA clones from different chromosomes, we demonstrate the accuracy and reliability of the mapping strategy.