Related Experiment Video
Updated: Aug 11, 2026
09:39
DNA Fingerprinting of Mycobacterium leprae Strains Using Variable Number Tandem Repeat (VNTR) - Fragment Length Analysis (FLA)
Published on: July 15, 2011
Evolution of short sequence repeats in Mycobacterium tuberculosis
Cath Arnold1, Nicola Thorne, Anthony Underwood
1Centre for Infections, Health Protection Agency, London, UK. catherine.arnold@hpa.org.uk
FEMS Microbiology Letters
|February 28, 2006
Summary
Mycobacterial interspersed repeat units (MIRUs) and variable number tandem repeat (VNTR) units are crucial for genotyping. This study found that modern bacterial strains globally tend to lose these repetitive DNA sequences compared to ancestral strains.
Area of Science:
- Genomics
- Microbiology
- Evolutionary Biology
Background:
- Short sequence repeats, including mycobacterial interspersed repeat units (MIRUs) and variable number tandem repeat (VNTR) units, are widely used for bacterial genotyping.
- These repetitive DNA elements are valuable markers for tracking bacterial populations and understanding their evolution.
Purpose of the Study:
- To investigate the evolutionary trends of selected short sequence repeats commonly used in bacterial genotyping schemes.
- To analyze the changes in repeat copy number in a large global collection of bacterial isolates.
Main Methods:
- Utilized deletion analysis, single nucleotide polymorphism (SNP) data, and spoligotype information from previously published studies.
- Examined the number of repeats per locus across over 400 bacterial isolates.
Main Results:
- Identified a global trend of repeat loss in modern bacterial strains when compared to ancestral strains.
- The analysis focused on repeats that are common denominators in established genotyping schemes.
Conclusions:
- The observed loss of repeats in modern strains suggests an evolutionary pressure or mechanism influencing the stability of these genomic regions.
- These findings have implications for the interpretation of genotyping data and understanding bacterial evolution over time.
Related Concept Videos
01:29Modern Molecular Taxonomy
Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...
01:08Evolution of Microbial Genome
Microbial genome evolution is a highly dynamic process shaped by continual gene gain and loss across species and strains. This genomic flexibility allows microorganisms to adapt rapidly to environmental pressures and interactions with other organisms. Central to understanding this diversity is the distinction between the core and pan genomes.The core genome comprises the genes shared by all sampled strains of a species, representing essential functions needed for fundamental cellular processes.
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
02:05Gene Evolution - Fast or Slow?
The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...
In contrast, regions which code...
01:23Tuberculosis
Tuberculosis (TB) remains a significant global health concern, primarily targeting the lungs and spreading through airborne transmission. Infection begins when aerosolized droplet nuclei, expelled by an individual with active TB, are inhaled by another person. These microscopic particles carry Mycobacterium tuberculosis, the causative agent of TB. Upon reaching the alveoli, the bacilli are engulfed by alveolar macrophages. However, due to their specialized lipid-rich cell wall, these pathogens...
01:25Mechanism of Antibiotic Resistance in MRSA
Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...