VARIABLE GERMLINE AND EMBRYONIC INSTABILITY OF THE HUMAN MINISATELLITE MS32 (D1S8) IN TRANSGENIC MICE

Tandem repeat loci such as minisatellites and trinucleotide repeats fr equently show instability, We have investigated mutation at human mini satellite MS32 (locus D1S8) transferred to transgenic mice, Three line s of hemizygous transgenic mice were studied. A single-copy line (110D ) was seen to be relatively stable, whilst two multicopy lines showed structural instability of the transgene in pedigrees (lines 109 and 11 0A), For both these lines, mutant structures were detected as a result of mutation events having occurred in the germline or early embryo, S tructural changes seen included gain or loss of minisatellite repeat u nits (110A and 109), alteration of DNA flanking the minisatellite repe at array (109 only) or deletion of the entire transgene (109 only). Th is work demonstrates that tandem repeat transgenes can show instabilit y and thus provide additional systems for the analysis of repetitive D NA structural change in mice.