02514nas a2200373   4500000000100000008004100001653002200042653002300064653002100087653003000108653002500138653002300163653001600186653003800202653003200240653002100272653001800293653001300311653001300324653002300337100001200360700001800372700001500390700001200405700001500417700001200432700001300444245011200457856007200569300001300641490000700654520146500661022001402126       2012                            d10aGenome, Bacterial10aGenetic Speciation10aGenes, Bacterial10aGene Transfer, Horizontal10aEvolution, Molecular10aBacterial Proteins10aHemerythrin10aInterspersed Repetitive Sequences10aMembrane Transport Proteins10aMultigene Family10aMycobacterium10aPlasmids10aProteome10aSelection, Genetic1 aSaini V1 aRaghuvanshi S1 aKhurana JP1 aAhmed N1 aHasnain SE1 aTyagi A1 aTyagi AK00aMassive gene acquisitions in Mycobacterium indicus pranii provide a perspective on mycobacterial evolution.  uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3505973/pdf/gks793.pdf  a10832-500 v403 a<p>Understanding the evolutionary and genomic mechanisms responsible for turning the soil-derived saprophytic mycobacteria into lethal intracellular pathogens is a critical step towards the development of strategies for the control of mycobacterial diseases. In this context, Mycobacterium indicus pranii (MIP) is of specific interest because of its unique immunological and evolutionary significance. Evolutionarily, it is the progenitor of opportunistic pathogens belonging to M. avium complex and is endowed with features that place it between saprophytic and pathogenic species. Herein, we have sequenced the complete MIP genome to understand its unique life style, basis of immunomodulation and habitat diversification in mycobacteria. As a case of massive gene acquisitions, 50.5% of MIP open reading frames (ORFs) are laterally acquired. We show, for the first time for Mycobacterium, that MIP genome has mosaic architecture. These gene acquisitions have led to the enrichment of selected gene families critical to MIP physiology. Comparative genomic analysis indicates a higher antigenic potential of MIP imparting it a unique ability for immunomodulation. Besides, it also suggests an important role of genomic fluidity in habitat diversification within mycobacteria and provides a unique view of evolutionary divergence and putative bottlenecks that might have eventually led to intracellular survival and pathogenic attributes in mycobacteria.</p>
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