Abstract
Horizontal gene transfer (HGT) was attributed as a major driving force for the innovation and evolution of prokaryotic genomes. Previously, multiple research endeavors were undertaken to decipher HGT in different bacterial lineages. The genus Mycobacterium houses some of the most deadly human pathogens; however, the impact of HGT in Mycobacterium has never been addressed in a systematic way. Previous initiatives to explore the genomic imprints of HGTs in Mycobacterium were focused on few selected species, specifically among the members of Mycobacterium tuberculosis complex. Considering the recent availability of a large number of genomes, the current study was initiated to decipher the probable events of HGTs among 109 completely sequenced Mycobacterium species. Our comprehensive phylogenetic analysis with more than 9,000 families of Mycobacterium proteins allowed us to list several instances of gene transfers spread across the Mycobacterium phylogeny. Moreover, by examining the topology of gene phylogenies here, we identified the species most likely to donate and receive these genes and provided a detailed overview of the putative functions these genes may be involved in. Our study suggested that horizontally acquired foreign genes had played an enduring role in the evolution of Mycobacterium genomes and have contributed to their metabolic versatility and pathogenicity.
Highlights
A significant fraction of genes in all living species was considered to be acquired from genealogically distant species[1,2,3,4,5,6,7]
The genera Rhodococcus, Gordonia, Segniliparus, Streptomyces and Tsukamurella were found to donate genes most frequently while at species level most of the foreign genes were found to come from Smaragdicoccus niigatensis DSM 44881 (22 events), Hoyosella subflava DQS3-9A1 (14 events), Tomitella biformata (29 events), Rhodococcus fascians (10 events) and Segniliparus rotundus DSM 44985 (12 events)
Our study suggested that most of Horizontal gene transfer (HGT) in the pathogenic group originated from phylum Actinobacteria (8 events), genus Rhodococcus (4 events) and Streptomyces (3 events), family Thermomonosporaceae (2 events) and several individual species like Actinomyces gerencseriae, Amycolatopsis methanolica and Brevibacterium senegalense
Summary
A significant fraction of genes in all living species was considered to be acquired from genealogically distant species[1,2,3,4,5,6,7]. Among the members of M. tuberculosis complex Those studies were conducted either on selected genomic regions[22,23,25] or considered only intra-genus gene exchanges between Mycobacterium species[24]. The main difference between the two approaches is that while phyletic pattern analysis depends on human expertise, T-REX infers probable HGTs based on statistical reconciliation of gene and species trees[32,33] Considering both these two approaches here we identified several instances of horizontal gene exchanges in Mycobacterium genomes which are described in subsequent sections with emphasis on their functional implications. Our study suggested that horizontally acquired foreign are integral to several biochemical pathways important for the survival of some Mycobacterium as pathogens
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
