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Low sequence variation in the gene encoding the human beta-myosin heavy chain
K Freeman1, K Nakao, L A Leinwand
1Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, USA.
Genomics
|September 11, 2001
Summary
Researchers analyzed the MYH7 gene in healthy individuals, finding low genetic variation. This suggests strong evolutionary pressure against mutations that could cause hypertrophic cardiomyopathy (FHC).
Area of Science:
- Genetics
- Molecular Biology
- Cardiovascular Research
Background:
- Familial hypertrophic cardiomyopathy (FHC) is linked to over 40 mutations in the MYH7 gene.
- No previous studies have investigated MYH7 genetic variation in the general population.
Purpose of the Study:
- To determine the extent and distribution of nucleotide variation in the MYH7 coding sequence in normal individuals.
- To compare MYH7 variation and evolutionary rate with other human genes and across species.
Main Methods:
- Sequencing of the 5808-bp MYH7 coding sequence in 25 healthy individuals.
- Identification and frequency analysis of single-nucleotide polymorphisms (SNPs).
- Comparative analysis of MYH7 homologous genes between human and rodent.
Main Results:
- Six single-nucleotide polymorphisms (SNPs) were identified, all silent (no amino acid change).
- Allele frequencies for the rarer allele ranged from 0.02 to 0.08.
- Nucleotide diversity (pi) was low (1.73x10^-4), lower than most human autosomal genes.
- MYH7 shows a very slow evolutionary rate, particularly in the alpha-helical myosin rod region.
Conclusions:
- The MYH7 gene exhibits exceptionally low nucleotide diversity in the human population.
- This low variation, including silent mutations, may result from strong selective pressure against mutations causing cardiomyopathy.
- Findings provide baseline data for MYH7 variation in normal populations and insights into its evolutionary constraints.