Only a few prominent simple sequence repeat (SSR) loci of the type (GATA)n are found in the genome of the mealmoth Ephestia kuehniella Zeller. Therefore this moth was chosen as a model organism for the genetic and molecular analysis of hypervariability of SSR loci. We characterized alleles of (GATA)n loci in different Ephestia strains by cloning and genomic restriction mapping. Some variants appeared to be mere variable number of tandem repeat (VNTR) alleles, others showed considerable changes in the sequence neighbourhood of the GATA repeats. These may be produced by major rearrangements or by transposition of the (GATA)n block together with flanking sequences into a different sequence environment.