Isolation of a Edna‐Derived Expressed‐Sequence‐Tag Clone on Chromosome 15

Complementary DNA clones isolated from human brain cDNA libraries have been partially DNA sequenced to generate expressed sequence tags (EST) (Adams et aI" 1992), ESTs have been essential for construction of transcript maps across large chromosome regions and for identification of genes responsible for inherited diseases and cancers, A procedure for rapid chromosomal assignment of EST has been developed (Polymeropoulos et at"~ 1992) , Pairs of oligonucleotide primers for each ESTs were used to amplify by PCR DNA template human-rodent somatic cell hybrid chromosomal panels, They were able to loca li ze 46 brain EST to chromosomes, One EST (ESTOO 165) was mapped to chromosome 15, the chromosome involved in Angelman syndrome (AS), a complex disorder characterized by severe mental retardation and puppet-like upperlimb movements, which is caused by deletions of proximal 15q (Knoll et aI., 1989), In our study, a genomic clone for this EST has been isolated and used to determine whether it maps to the AS chromosome region.