The DATA= data set has columns representing markers, ID variables, and a trait, and rows representing the individuals. There must be one binary trait variable listed in the TRAIT statement; the three ID variables consisting of the individual’s ID and the two parental IDs, all of the same type, must be listed in the ID statement, and optionally the pedigree ID if the individual identifiers are not unique. Note that only individuals with both parents appearing in the data, even if all the parents’ genotypes are missing, can be used as affected children or in sib pairs for analysis. However, if the individual is used only as a parent, then that individual’s parents need not appear in the data. An individual’s parents must occur in the data set before the individual does, and full siblings must be in consecutive observations. If a pedigree ID variable is specified in the ID statement, any individual with a missing value for that variable is excluded from the analysis, as a parent and as a child. There are two columns for each marker, representing the two alleles at that marker carried by the individual. These two columns must be listed consecutively in the VAR statement. These marker variables must all be of the same type, but can be either character or numeric variables.