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Phenotypic variance explained by local ancestry in admixed African Americans
Daniel Shriner1, Amy R Bentley1, Ayo P Doumatey1
1Center for Research on Genomics and Global Health, National Human Genome Research Institute Bethesda, MD, USA.
Frontiers in Genetics
|November 19, 2015
Summary
Local ancestry explains significant phenotypic variance in African Americans, up to 20% for major genes. This impacts understanding genetic risk factors and association study accuracy.
Area of Science:
- Population Genetics
- Human Genetics
- Genomics
Background:
- Admixed populations like African Americans have complex genetic ancestry.
- Understanding the genetic basis of phenotypic variation is crucial for health research.
Purpose of the Study:
- To quantify the proportion of phenotypic variance explained by local ancestry in African Americans.
- To assess the impact of local ancestry on genetic risk factors and association studies.
Main Methods:
- Inferred local ancestry across the genome in African Americans.
- Utilized linear mixed effects models to estimate variance explained by local ancestry.
- Analyzed 26 quantitative traits and disease outcomes in two independent samples.
Main Results:
- Local ancestry explained up to 20% of phenotypic variance at major effect genes.
- Local ancestry explained up to 8% of phenotypic variance for polygenic effects.
- Found that most additive genetic variance is captured by ancestry-undifferentiated markers.
Conclusions:
- Local ancestry is a significant contributor to phenotypic variation in African Americans.
- Results inform the genetic contribution to health disparities and potential biases in genetic association studies.
- Highlights the importance of considering local ancestry in genetic research within admixed populations.
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