Related Experiment Video
Updated: Feb 2, 2026

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Segmental Variation in a Duplicated msp2 Pseudogene Generates Anaplasma marginale Antigenic Variants
Telmo Graça1, Pei-Shin Ku2,3, Marta G Silva3
1Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, USA telmo.graca@wsu.edu.
Anaplasma marginale uses gene duplication of major surface protein 2 (Msp2) pseudogenes to create antigenic variants. This allows the bacterium to evade host immunity and establish persistent infections.
Area of Science:
- Bacteriology
- Immunology
- Genomics
Background:
- Anaplasma marginale causes persistent infections through antigenic variation of major surface protein 2 (Msp2).
- Msp2 diversity is generated by gene conversion of chromosomally encoded pseudogenes.
- Previous analysis showed identical Msp2 pseudogenes in some strains, suggesting a role for gene duplication.
Purpose of the Study:
- To investigate the hypothesis that Anaplasma marginale's Msp2 pseudogene repertoire arises from gene duplication.
- To understand the evolutionary mechanisms driving Msp2 diversity and immune evasion.
Main Methods:
- Comparative genomics of Anaplasma marginale strains.
- Analysis of Msp2 pseudogene sequences and locus structures.
- Assessment of immune escape capabilities linked to pseudogene variations.
Main Results:
- Gene duplication of Msp2 pseudogenes is common across Anaplasma marginale strains.
- Duplicate pseudogene pairs were found to be either identical or contain segmental changes.
- Minimal changes in duplicated pseudogenes, or divergent sequences, were sufficient for immune escape.
Conclusions:
- A model where Msp2 pseudogene loci duplicate, allowing one copy to accumulate changes, supports repertoire generation.
- This process enables the creation of sufficient antigenic variants for immune evasion and persistent infection.
- Gene duplication is a key mechanism for Anaplasma marginale's adaptability and pathogenicity.
Related Concept Videos
Histone Variants at the Centromere
Centrosome Duplication
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
What is Variation?
The range, standard deviation, standard error, and variance are the different measures of variation.
Range: The range is the difference between its maximum and...
Gene Duplication and Divergence
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are...
Conservative Site-specific Recombination and Phase Variation
The recognition sites for Cre recombinase called LoxP...
Duplication of Chromatin Structure
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...

