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MTGSAM: Multiple-Trait Gibbs Sampler for Animal Models

posted on 2023-12-18, 18:05 authored by Curtis P. Van Tassell, Lloyd Dale Van Vleck

A set of FORTRAN programs to implement a multiple-trait Gibbs sampling algorithm for (co)variance component inference in animal models (MTGSAM) was developed. The MTGSAM programs are available to the public. The programs support models with correlated genetic effects and arbitrary numbers of covariates, fixed effects, and independent random effects for each trait. Any combination of missing traits is allowed. The programs were used to estimate variance components for 50 replicates of simulated data. Each replicate consisted of 50 animals of each sex in each of four generations, for 400 animals in each replicate for two traits. For MTGSAM, informative prior distributions for variance components were inverted Wishart random variables with 10 df and means equal to the simulation parameters. A total of 15,000 Gibbs sampling rounds were completed for each replicate, with 2,000 rounds discarded for burn-in. For multiple-trait derivative free restricted maximum likelihood (MTDFREML), starting values for the variance components were the simulation parameters. Averages of posterior mean of variance components estimated using MTGSAM with informative and flat prior distributions for variance components and REML estimates obtained using MTDFREML indicated that all three methods were empirically unbiased. Correlations between estimates from MTGSAM using flat priors and MTDFREML all exceeded .99.

Resources in this dataset:




Data contact name

Van Tassell, Curt

Data contact email


United States Department of Agriculture


  • Not specified

ISO Topic Category

  • biota

National Agricultural Library Thesaurus terms

computer software; models; animal models; algorithms; covariance; variance; animals; statistical analysis

OMB Bureau Code

  • 005:18 - Agricultural Research Service

OMB Program Code

  • 005:040 - National Research

Primary article PubAg Handle

Pending citation

  • No

Public Access Level

  • Public

Preferred dataset citation

Van Tassell, Curtis P.; Van Vleck, Lloyd Dale (2019). MTGSAM: Multiple-Trait Gibbs Sampler for Animal Models. United States Department of Agriculture.

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