MRVTEST

MRVTEST performs likelihood-based combined linkage and association analyses across transmission models to detect genetic effects at specific loci, building on the likelihood-based model-free linkage framework of MFLINK.

Key Features:

• Transmission model flexibility: Addresses misspecification of transmission model parameters that can produce artifactually negative LOD scores at small recombination fractions and in multipoint analyses and focuses detection on genetic effects at loci rather than precise map position estimation.
• Likelihood maximization: Maximizes likelihoods over transmission and linkage parameters while constraining transmission parameters to reflect population prevalence to avoid biased parameter estimates that reduce linkage detection power.
• Independent likelihood maximization: Independently maximizes likelihoods under linkage and non-linkage over a limited set of transmission models ranging from Mendelian dominant to null effect and from null effect to Mendelian recessive.
• Admixture consideration: Incorporates admixture by maximizing the linkage likelihood over the proportion of families linked at a given map position.
• Applicability to various data types: Applies to affected sib-pair and pedigree data and maintains LOD scores at test positions near markers, supporting multipoint analyses.
• Minimal transmission model specification: Requires only an approximate estimate of population prevalence rather than detailed specification of transmission model parameters.

Scientific Applications:

• Linkage and association analysis: Combined likelihood analyses to detect genetic linkage and association signals under multiple transmission models.
• Detection of locus-specific effects: Identifying genetic effects at specific loci while avoiding artefacts from model misspecification.
• Family-based study analysis: Analysis of affected sib-pair studies and pedigrees, including multipoint marker analyses.

Methodology:

Maximizes likelihoods over linkage and transmission parameters with constraints to population prevalence, performs independent likelihood maximization under linkage and non-linkage across specified transmission models (Mendelian dominant → null → Mendelian recessive), and maximizes the linkage likelihood over the proportion of families linked at each map position to model admixture.