Did the loss of sigma factors initiate pseudogene accumulation in M. leprae?

Pseudogenes are non-functional regions in the genome that have arisen as a consequence of accumulating mutations that either result in the premature termination of proteins during protein synthesis or the disruption of transcription. There have been various discussions of the origins of pseudogenes and the models for their formation, but there has been little input on how pseudogenes could have accumulated in an organism. In this brief communication, I propose a two-step model for the accretion of pseudogenes in the Mycobacterium leprae genome, triggered by the loss of different sets of sigma factors at different time points during the course of evolution.