THE FREQUENCY OF MINISATELLITE AND MICROS ATELLITE IN THE HUMAN 13TH CHROMOSOME

The frequency of specific mini- and microsatellites known also as shor t tandem repeated sequences (STR) in the human 13 chromosome was estim ated by hybridization of STR core oligonucleotides to recombinant cosm ide clones transferred to a grid from a human 13 chromosome specific c osmide library ICRF Lawrist 4 C108 (DN LA/HS 13). Oligonucleotides: M1 3 and Jeffreys minisatellite core sequences and microsatellite core se quences (TCC)5, (CAC)5, and (GACA)4 were [gamma-P-32] end labeled and hybridized to membrane filters carrying good ordered cosmide clones. I t was shown that great number of all these mini- and microsatellite co pies (besides of Jeffreys minisatellite) are spread independently alon g the 13th chromosome. It was also estimated that two or more (GACA)n blocks present in the same cosmid (i.e. on the stretch of 40-50 kb) fo rming similar groups of clastered microsatellites. The interesting pec uliarity has been recorded that some (GACA)n+ cosmides are also hybrid azable to conservative 28SrDNA 3'-fragment that indicates the (GACA)n localization in the nucleoli area. As the result of it we began the cr eation of a new highly polymorfic markers collections for these chromo some.