The genomic distribution of the abundant eukaryotic d(GA x TC)(n) DNA 
microsatellite suggests that it could contribute to DNA recombination. Here, it 
is shown that this type of microsatellite DNA sequence enhances DNA 
recombination in SV40 minichromosomes, the rate of homologous DNA recombination 
increasing by as much as two orders of magnitude in the presence of a d(GA x 
TC)(22) sequence. This effect depends on the region of the SV40 genome at which 
the d(GA x TC)(22) sequence is cloned. It is high when the sequence is located 
proximal to the SV40 control region but no effect is observed when located 3.5 
kb away from the SV40 ori. These results indicate that the recombination 
potential of d(GA x TC)(n) sequences is likely linked to DNA replication and/or 
transcription. The potential contribution of the structural properties of d(GA x 
TC)(n) sequences to this effect is discussed.