COMPARATIVE STUDY OF OVERLAPPING GENES IN THE GENOMES OF MYCOPLASMA HOMINIS AND MYCOPLASMA PENETRANS

摘要

Overlapping genes are pairs of adjacent genes whose coding regions are partially or entirely overlapping. Overlapping genes in prokaryotes are a means to minimize genome size and increase the density of genetic information. Overlapping genes play an important role in genome reduction of Mycoplasmas during the course of their degenerative evolution. In this study overlapping genes in the genomes of two obligatory human parasites, Mycoplasma hominis and Mycoplasma penetrans were extracted and systematically analyzed. Overlapping genes were classified into different categories based on their direction of transcription. Gene pairs that occur as overlapping in both the genomes, gene pairs that occur as overlapping in one genome but are split in the other genome were separated out and more closely analysed. The study revealed that most of the overlapping genes in these genomes are formed due to loss of a stop codon or frame shift. The present study also emphasizes the significance of overlapping genes in the evolution of these genomes.