Linkage detection adaptive to linkage disequilibrium: the disequilibrium maximum-likelihood-binomial test for...

Area of Science:

• Genetics
• Statistical genetics
• Bioinformatics

Background:

• The transmission/disequilibrium test (TDT) and affected-sib-pair (ASP) mean test have varying power based on linkage disequilibrium (LD) strength.
• TDT is powerful with strong LD, while the mean test excels with weak or absent LD.
• Determining LD extent in practice is challenging, necessitating adaptive methods.

Purpose of the Study:

• To develop a novel statistical test for genetic linkage analysis that is adaptive to the extent of linkage disequilibrium (LD).
• To propose the disequilibrium maximum-binomial-likelihood (DMLB) test, integrating LD information into linkage detection for affected-sib-pair (ASP) data.

Main Methods:

• Introduction of the disequilibrium maximum-binomial-likelihood (DMLB) test.
• The DMLB test adaptively combines identity-by-descent (IBD) sharing scores with allele-specific IBD sharing contrasts.
• Evaluation of the DMLB test's performance compared to TDT and mean tests using simulated data.

Main Results:

• The DMLB test demonstrated higher statistical power than both TDT and the mean test for ASP data when linkage disequilibrium (LD) ranged from moderate to strong.
• The DMLB test showed slightly lower power than the mean test only in cases of very weak or absent LD.
• The TDT exhibited negligible power in scenarios with very weak or absent LD.

Conclusions:

• The disequilibrium maximum-binomial-likelihood (DMLB) test is a robust approach for genetic linkage detection, particularly when the extent of linkage disequilibrium (LD) is unknown.
• The DMLB test offers an adaptive strategy, outperforming existing methods like TDT and mean tests across a spectrum of LD conditions.
• This method provides a valuable tool for genetic studies aiming to identify disease-predisposing mutations.