AHRR Locus CpG Methylation Analysis for Smoking Status
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Solution Overview
Problem
Current methods for determining DNA methylation status to distinguish current smokers from never smokers are labor-intensive, require large DNA samples, and are not suitable for forensic or clinical applications due to their complexity and sample quantity demands.
Innovation Solution
A method using PCR amplification and pyrosequencing to analyze specific CpG sites at the AHRR locus in genomic DNA, allowing for accurate and rapid identification of smoking habits with minimal DNA samples, and applicable in high-throughput formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chip array-based platforms are used to investigate differentially methylated loci, then broader investigation and identification of differentially methylated loci is enabled, but the method requires large amounts of DNA and laborious bioinformatic analysis
Solution Approach 1:
The patent extracts and focuses analysis on a specific, limited number of CpG sites (5-10 sites) within the AHRR locus that are most strongly associated with smoking status, rather than analyzing the entire genome or all CpG sites. This selective extraction maintains the ability to identify smoking status while dramatically reducing bioinformatic complexity and DNA requirements
Solution Approach 2:
The patent segments the complex genome-wide methylation analysis into a focused examination of specific CpG sites within a single gene locus (AHRR). By dividing the problem into manageable, pre-selected segments (specific CpG sites), the methodology reduces overall complexity while maintaining diagnostic accuracy for smoking status identification
2Measurement precision
If chip array-based platforms are used to determine DNA methylation status, then identification of differentially methylated loci is enabled, but large amounts of DNA and laborious analysis are required
Solution Approach 1:
The patent extracts only the essential information needed for smoking status determination from the AHRR locus by focusing on 5-10 specifically selected CpG sites, rather than requiring comprehensive genome-wide analysis. This selective extraction maintains measurement precision for smoking status while reducing the quantity of DNA material required
Solution Approach 2:
The patent applies partial action by analyzing only a subset of CpG sites (5-10 sites) within the AHRR locus rather than examining all possible CpG sites in the genome. This partial analysis is sufficient to achieve accurate smoking status determination, thereby reducing DNA quantity requirements without sacrificing measurement precision
3Reliability
If conventional DNA methylation methods are used to distinguish smokers from non-smokers, then smoking status identification is enabled, but the methods are labor-intensive and not suitable for high-throughput applications
Solution Approach 1:
The patent segments the smoking status determination process into a streamlined workflow focusing on a limited number of CpG sites that can be processed in parallel using high-throughput sequencing. This segmentation enables accurate identification while dramatically increasing productivity by eliminating the need for complex, labor-intensive genome-wide analysis
Solution Approach 2:
The patent changes the analytical parameters from comprehensive genome-wide methylation profiling to focused analysis of 5-10 specific CpG sites. This parameter change maintains reliable smoking status identification while enabling high-throughput processing by reducing the complexity and time required for analysis
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick, cost-effective, and sensitive determination of smoking status, differentiating between current, former, and never smokers, with high accuracy and specificity, suitable for forensic and clinical use.
Implementation Method 1
The bisulfite chemically converts the unmethylated cytosines to uracils but does not react with methylated cytosines
Implementation Method 2
DNA methylation occurs through methylation of cytosine residues in the CpG dinucleotide sites by DNA methyl transferases (DNMT)
Implementation Method 3
the amplicons can then be sequenced to determine the presence of a cytosine or a thymine at each specific CpG
Data Source
AI summary
The subject invention pertains to biomarkers for identifying the source of a cell as a current, former, or never smoker. In certain embodiments, the methylation status at the AHRR locus in the genomic DNA isolated from a cell is determined by pyrosequencing technique using specific primers described herein. Kits containing primers and reagents for carrying out the methods disclosed herein are also provided.