COSMID-DERIVED TRANSCRIPTS AND SEQUENCE TAGS MAPPED TO 3 SUBREGIONS OF HUMAN-CHROMOSOME-22

Fifty cosmids from the ICRF, London, and Lawrence Livermore Laboratory , California, human chromosome 22 cosmid libraries were isolated, regi onally assigned and tested for their ability to detect repeats or sing le copy sequences. The search resulted in nine cosmids containing repe titive motifs from the pericentric region of chromosome 22. An additio nal 19 cosmids, that detected single copy sequences in the long arm of chromosome 22q: 7 in the region 22q11.2-q13.1 and 12 in 22q13.1-qter, were mapped more precisely by fluorescence in situ hybridization. Thr ee out of these 19 recombinants displayed restriction fragments contai ning (CA)(n) repeats, were subcloned and sequenced. One cosmid, repres enting a region coding for an ubiquitous 300-bp transcript, is localiz ed 600 kb from PDGFB, and four cosmids contained sequences surrounding the ARSA gene at 22q13.3. Presently, long range physical maps, that m ay be useful for analysing structural alterations of chromosome 22q13, are being constructed from these additional, regionally assigned mark ers from chromosome 22q13 employing both existing cosmid and new bacte rial artificial chromosome (BAC) libraries.