Identifying Causal Genotype-Phenotype Relationships for Population-Sampled Parent-Child Trios

Area of Science:

• Genetics
• Biostatistics
• Causal Inference

Background:

• Genetic transmission introduces randomization prior to other causal factors influencing child phenotypes.
• Parent-child trio data can be modeled to understand genetic transmission as a source of experimental randomization.

Purpose of the Study:

• To develop and validate new statistical methods for identifying causal genetic loci using parent-child trio data.
• To model genetic transmission as a source of randomization for causal inference.

Main Methods:

• Development of the transmission mean test (TMT) and its unbiased estimator for average causal effect.
• Derivation of causal properties of the TMT within the potential outcomes framework.
• Proof that the transmission disequilibrium test (TDT) is a complementary case of the TMT for affected-only designs.

Main Results:

• The TMT is suitable for arbitrarily distributed traits and randomly sampled trios.
• The TDT is appropriate for dichotomous traits and trait-based sampling.
• Comparison of transmission-based methods with established genotype-phenotype analyses.

Conclusions:

• Transmission-based methods offer powerful tools for causal genetic discovery.
• The choice between TMT and TDT depends on trait distribution and study design.
• Integrating transmission-based methods with other approaches enhances genotype-phenotype analysis.