GS3 is a program that estimates fixed and random effects, breeding values and SNP effects for genomic selection. It includes normal, mixture, or double exponential distributions for SNP effects, i.e. GBLUP, the so-called BayesCPi, and the Bayesian Lasso. It allows estimation of the variances and effects of SNPs, polygenic and environmental effects, and also the inclusion of heterogeneous variances as for the analysis of DYD's. As of December 2010, the software has been rewritten to allow for more user-friendly data files; as of August 2011, the Bayesian Lasso has been included.