Related Experiment Video
Updated: Mar 1, 2026

Phage-Mediated Genetic Manipulation of the Lyme Disease Spirochete Borrelia burgdorferi
Published on: September 28, 2022
Massive gene decay in the leprosy bacillus.
S T Cole1, K Eiglmeier, J Parkhill
1Unité de Génétique Moléculaire Bactérienne, Institut Pasteur, Paris, France. stcole@pasteur.fr
The leprosy bacterium, Mycobacterium leprae, has undergone extreme genome reduction, losing many genes and metabolic functions. This explains its slow growth and inability to be cultured in labs, offering insights into this chronic neurological disease.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Leprosy is a chronic neurological disease caused by Mycobacterium leprae.
- Mycobacterium leprae exhibits the longest bacterial doubling time and is unculturable.
- It is a close relative of Mycobacterium tuberculosis.
Purpose of the Study:
- To compare the genome sequence of Mycobacterium leprae with Mycobacterium tuberculosis.
- To understand the properties of Mycobacterium leprae, including its slow growth and unculturability.
- To investigate the phenomenon of reductive evolution in Mycobacterium leprae.
Main Methods:
- Genome sequencing of an armadillo-derived Indian isolate of Mycobacterium leprae (3.27 Mb).
- Comparative genomics with Mycobacterium tuberculosis (4.41 Mb).
Main Results:
- Mycobacterium leprae's genome has undergone extreme reductive evolution.
- Less than half of the Mycobacterium leprae genome contains functional genes; pseudogenes are abundant.
- Genome downsizing and mosaic arrangement are attributed to recombination events.
- Significant loss of metabolic activities, including siderophore production and respiratory chains.
Conclusions:
- The reduced genome explains Mycobacterium leprae's slow growth and inability to be cultured.
- Reductive evolution has led to the loss of essential metabolic pathways.
- Comparative genomics reveals insights into bacterial adaptation and pathogenesis.
More Related Videos
10:32Optimized Protocols for Mycobacterium leprae Strain Management: Frozen Stock Preservation and Maintenance in Athymic Nude Mice
Published on: March 23, 2014
09:39DNA Fingerprinting of Mycobacterium leprae Strains Using Variable Number Tandem Repeat VNTR - Fragment Length Analysis FLA
Published on: July 15, 2011
Related Concept Videos
Genomic DNA in Prokaryotes
Genomic Diversity in Bacteria
Although bacterial genomes are much...
Viral Replication: Lysogenic Cycle
Mutations in Microorganisms
Coordination of Gene Expression Processes in Bacteria
Gene Evolution - Fast or Slow?
In contrast, regions which code...
Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...