ISOLATION AND REGIONAL MAPPING OF CDNAS EXPRESSED DURING EARLY HUMAN-DEVELOPMENT

A cDNA sequencing project was initiated with the aim of isolating and mapping new genes expressed during early human development. A human em bryo cDNA library was constructed, and a prescreening procedure was us ed to select cDNAs corresponding to poorly transcribed genes. Partial sequences were generated from one or both ends of 231 cDNA clones, and sequence comparison with genetic databases revealed that 28% were alr eady annotated genes, 42% matched with partial sequences expressed seq uence tags that had already been detected, 3% contained no insert, 5% were highly similar to sequences hom other species, and 23% of the cDN As appeared to be unknown in genetic databases. All new sequences were deposited in public genetic databases, and most of the corresponding cDNAs were regionally mapped on human chromosome bands using both fluo rescence and radioactive in situ hybridization. Several cDNAs colocali zed with critical regions of the genome regarding mapped disorders, th us providing candidate genes for human genetic diseases. (C) 1997 Acad emic Press