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In vivo human somatic mutation: frequency and spectrum with age
S A Grist1, M McCarron, A Kutlaca
1Department of Hematology, Flinders Medical Centre, Bedford Park, SA, Australia.
Mutation Research
|April 1, 1992
Summary
The frequency of mutations in human lymphocytes increases with age, with gene recombination being a significant factor. This study analyzed mutations at the HLA-A locus to understand age-related genetic changes.
Area of Science:
- Immunogenetics
- Human Genetics
- Molecular Biology
Background:
- The accumulation of somatic mutations is linked to aging and disease.
- Understanding the molecular basis of mutations in human lymphocytes is crucial for aging research.
Purpose of the Study:
- To investigate the relationship between age and the frequency and molecular nature of in vivo mutations at the human HLA-A locus.
- To determine the proportion of clonally related mutants and the mechanisms underlying mutation development.
Main Methods:
- Immunoselection and limiting dilution cloning of mutant human lymphocytes.
- Southern blotting to analyze HLA-A gene dosage and loss of heterozygosity.
- Analysis of T lymphocyte receptor gene rearrangements to estimate clonal relatedness.
Main Results:
- Mutant lymphocyte frequency significantly increased with age, from 0.71 x 10(-5) in neonates to 6.53 x 10(-5) in the elderly.
- Mitotic recombination accounted for 32.5% of mutations, with a random distribution of crossing-over points.
- The proportion of recombination mutants varied significantly between individuals and increased with age.
Conclusions:
- Age-dependent increases in specific mutation types, particularly mitotic recombination, occur in human lymphocytes.
- Individual variability exists in mutation mechanisms, suggesting distinct genetic susceptibility or repair efficiencies.
- The findings provide insights into the molecular drivers of aging and potential disease risk.