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Evolution of the mannose-binding lectin gene in primates
M V Verga Falzacappa1, L Segat, B Puppini
1Genetic Section, Department of Reproductive and Developmental Sciences, University of Trieste, Via dell'Istria 65/1, Trieste, Italy. MaVi.Verga-Falzacappa@med.uni-heidelberg.de
Genes and Immunity
|October 16, 2004
Summary
The mannose-binding lectin (MBL2) gene is highly conserved across primate species, crucial for innate immunity. Unlike humans, non-human primates show limited MBL2 genetic variation, highlighting its evolutionary stability.
Area of Science:
- Immunology
- Evolutionary Biology
- Genetics
Background:
- Mannose-binding lectin (MBL2) is a key component of the innate immune system.
- MBL2 functions as an opsonin and activates the complement system by binding to carbohydrate surfaces.
- Understanding MBL2 gene evolution provides insights into immune defense mechanisms across species.
Purpose of the Study:
- To investigate the evolutionary conservation of the MBL2 gene in primates.
- To compare the MBL2 coding sequences between humans and 12 non-human primate species.
- To identify potential selective pressures and variations within the MBL2 gene across primate evolution.
Main Methods:
- Sequencing of the MBL2 gene's coding region in 12 non-human primate species.
- Comparative analysis of nucleotide and amino-acid sequences with human MBL2.
- Phylogenetic analysis to assess evolutionary relationships and selective pressures.
Main Results:
- High homology in nucleotide and amino-acid sequences of MBL2 among primates was observed.
- The collagen-like domain of MBL2 showed particularly high sequence identity across primates.
- Primate-specific mutations were found in the carbohydrate recognition domain, without affecting structure or function.
- Phylogenetic analysis revealed no positive selective pressure on the MBL2 gene in non-human primates.
Conclusions:
- The MBL2 gene is highly conserved in non-human primates, reflecting its vital role in immune defense.
- Non-human primates exhibit less genetic 'plasticity' in MBL2 compared to humans, where higher variation exists.
- The conserved nature of MBL2 underscores its fundamental importance in the primate immune system.