Satellite DNA variation in parental and derived unisexual hybrids of Bacillus stick insects (Phasmatodea)

The Bag320 sequence family of satellite DNA (satDNA) has been found in some stick insect taxa: the bisexual Bacillus grandii, the related parthenogen B. atticus and their hybrids with B. rossius. However, under the same experimental conditions, the Bag320 sequences were not found in B. rossius. Bag320 sequences of the clonal hybrid B. whitei (= B. rossius/grandii grandii) intermingled with those of B. grandii in all plotted dendrograms. On the whole, satDNA features (restriction pattern, sequence variation, fluorescent in situ hybridization (FISH)), allozymes and karyology support a relatively recent origin of B. whitei. Our investigations on unisexual hybrids of Bacillus also suggested that their origin and clonal reproduction allow the occurrence of different sequence subsets of limited variability in isolated populations stemming from the hybridization focus.