An approach for genome analysis based on assembly of fragments of DNA from the whole genome can be applied to obtain the complete nucleotide sequence of the genome of Zymomonas mobilis. However, the problem of fragment assembly raise thorny computational issues. Computer simulation studies of sequence assembly usually show some abnormal assemblage of artificial sequences containing repetitive or duplicated regions, and suggest methods to correct those abnormalities. In this paper, we describe five simulation studies which had been performed previous to the actual genome assembly process of Zymomonas mobilis ZM4.