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Issues in genomic screening: critical values, sample sizes, and the ability to detect linkage
1Program for Population Genetics, Harvard School of Public Health, Boston, MA 02115, USA.
Genetic Epidemiology
|December 22, 1999
Summary
This study shows that larger sample sizes of affected sib pairs (ASPs) improve gene localization accuracy. Genome-wide significance for gene mapping is achievable with 400 or more ASPs.
Area of Science:
- Genetics
- Statistical Genetics
- Bioinformatics
Background:
- Gene localization is crucial for understanding genetic diseases.
- Affected sib pair (ASP) designs are a common strategy for gene mapping.
- Accurate estimation of statistical thresholds (lod score critical values) is essential for reliable gene discovery.
Purpose of the Study:
- To empirically assess the power of ASPs for gene localization.
- To compare lod score critical value estimation methods.
- To evaluate the impact of sample size on gene mapping success.
Main Methods:
- Simulated 25 replicates of 100 nuclear families.
- Created datasets of varying sizes (100 to 1,000 ASPs).
- Calculated maximum lod scores across a six-chromosome genome.
- Determined genome-wide significance thresholds using Lander-Kruglyak and resampling methods.
Main Results:
- Gene detection ability of ASPs increased with sample size.
- Genome-wide significance was achieved with 400 or more ASPs.
- Resampling-based critical values were slightly lower than theoretical values.
Conclusions:
- Larger sample sizes enhance the power of ASPs for gene localization.
- Resampling offers a flexible alternative for determining significance thresholds in genetic studies.
- The findings support the utility of ASP designs in complex trait gene mapping.