Happy is an R interface into the HAPPY C package for fine-mapping Quantitative Trait Loci (QTL) in Heterogenous Stocks (HS). An HS is an advanced intercross between (usually eight) founder inbred strains of mice. HS are suitable for fine-mapping QTL. It uses a multipoint analysis which offers significant improvements in statistical power to detect QTLs over that achieved by single-marker association.

The happy package is an extension of the original C program happy; it uses the C code to compute the probability of descent from each of the founders, at each locus position, but the happy packager allows a much richer range of models to be fit to the data.

Read /usr/share/doc/r-other-mott-happy/README.Debian for a more detailed explanation.