ISOLATION AND REFINED REGIONAL MAPPING OF EXPRESSED SEQUENCES FROM HUMAN-CHROMOSOME-21

To increase candidate genes from human chromosome 21 for the analysis of Down syndrome and other genetic diseases localized on this chromoso me, we have isolated and studied 9 cDNA clones encoded by chromosome 2 1. For isolating cDNAs, single-copy microclones from a chromosome 21 m icrodissection Library were used in direct screening of various cDNA l ibraries. Seven of the cDNA clones have been regionally mapped on chro mosome 21 using a comprehensive hybrid mapping panel comprising 24 cel l hybrids that divide the chromosome into 33 subregions. These cDNA cl ones with refined mapping positions should be useful for identificatio n and cloning of genes responsible for the specific component phenotyp es of Down syndrome and other diseases on chromosome 21, including pro gressive myoclonus epilepsy in 21q22.3. (C) 1994 Academic Press, Inc.