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Length and sequence variation in the apolipoprotein B intron 20 Alu repeat
M D Shriver1, G Siest, E Boerwinkle
1Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston 77225.
Genomics
|October 1, 1992
Summary
We developed a new method to analyze variations in the human apolipoprotein B gene. This approach efficiently identifies both sequence and length differences in the Alu element, aiding genetic studies.
Area of Science:
- Genetics
- Molecular Biology
Background:
- The human apolipoprotein B (apo B) gene plays a crucial role in lipid metabolism.
- Genetic variations within the apo B gene can be associated with various health conditions.
- Intron 20 of the apo B gene contains an Alu element with potential for sequence and length polymorphisms.
Purpose of the Study:
- To develop and validate a novel Single-Stranded Conformation Polymorphism (SSCP) protocol.
- To analyze sequence and length variations within the Alu element in intron 20 of the human apo B gene.
- To assess the utility of this method for genetic typing and haplotype construction.
Main Methods:
- Developed a Single-Stranded Conformation Polymorphism (SSCP) protocol.
- Utilized Polymerase Chain Reaction (PCR) for amplification and isotopic labeling of the apo B intron 20 Alu element.
- Employed PstI restriction enzyme digestion to separate the Alu tail (IN20-REP) from the Alu body (IN20-SEQ).
- Sequenced all identified alleles to confirm variations and identify additional undetected alleles.
Main Results:
- Identified 11 sequence-distinct alleles at the IN20-SEQ locus and 7 alleles with combined sequence and length variations at the IN20-REP locus in 242 unrelated French individuals.
- Discovered one additional allele at each locus through sequencing that was not detected by SSCP.
- Observed that while numerous alleles exist, a few common alleles predominated, accounting for over 94% of the sampled population.
- Verified Mendelian segregation of both loci and constructed haplotypes using family data.
Conclusions:
- The developed SSCP protocol effectively distinguishes sequence and length variations in the apo B intron 20 Alu element.
- The method provides a powerful tool for genetic typing of the apo B gene, revealing significant allelic diversity.
- The findings support the use of this approach for population genetics studies and the construction of genetic markers.