An imputed ancestral reference genome for the Mycobacterium tuberculosis complex better captures structural genomic
Luke B Harrison1,2, Vivek Kapur3, Marcel A Behr1,4
1Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada.
Microbial Genomics
|January 4, 2024
Summary
A new ancestral reference genome, MTBC0, improves short-read mapping and SNP calling for Mycobacterium tuberculosis complex (MTBC) genomic analysis. This enhanced reference better captures genomic variation and structural evolution in MTBC studies.
Area of Science:
- Genomics
- Microbiology
- Bioinformatics
Background:
- Reference-based alignment is crucial for Mycobacterium tuberculosis complex (MTBC) genomic analysis.
- Current references like H37Rv and Comas et al. do not fully represent MTBC structural variation.
- This limits comprehensive genomic interpretation.
Purpose of the Study:
- To develop a more representative ancestral reference genome for MTBC.
- To evaluate the performance of this new reference (MTBC0) in standard genomic analysis workflows.
Main Methods:
- Generated an imputed ancestral genomic sequence (MTBC0) using reference-free alignments of closed MTBC genomes.
- Utilized MTBC0 as a reference sequence in short-read alignment workflows.
- Compared mapping efficiency and SNP calling against existing references (Comas et al., H37Rv).
Main Results:
- MTBC0 mapped more short sequencing reads and identified more pairwise SNPs compared to the Comas et al. reference.
- MTBC0 demonstrated greater fidelity in capturing genomic variation, including regions absent in H37Rv.
- Phylogenetic analysis showed minimal impact on the overall MTBC phylogeny.
Conclusions:
- MTBC0 enhances standard MTBC workflows by improving read mapping and SNP calling.
- This ancestral reference facilitates the study of structural variation and evolution within the MTBC.
- MTBC0 offers greater accuracy for genomic analyses of Mycobacterium tuberculosis complex.
