Comparative genomics ofMycobacterium africanumLineage 5 and Lineage 6 from Ghana suggests different ecological niches

Abstract

37Mycobacterium africanum (Maf) causes up to half of human tuberculosis in West Africa, but little is 38 known on this pathogen. We compared the genomes of 253 Maf clinical isolates from Ghana, 39 including both L5 and L6. We found that the genomic diversity of L6 was higher than in L5, and 40 the selection pressures differed between both groups. Regulatory proteins appeared to evolve 41 neutrally in L5 but under purifying selection in L6. Conversely, human T cell epitopes were under 42 purifying selection in L5, but under positive selection in L6. Although only 10% of the T cell 43 epitopes were variable, mutations were mostly lineage-specific. Our findings indicate that Maf L5 44 and L6 are genomically distinct, possibly reflecting different ecological niches. 45 46 47. CC-BY 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.