Use this field to specify those variables with which to form interactions with each of the
SNPs. Thus, in addition to the tests performed on each individual SNP after adjusting for the fixed and
random effects, a test is performed on the interaction of each of the effects listed in this field with each of the SNPs individually adjusting for the fixed and random effects. These effects can be interactions themselves.
The test statistic for entering the interaction of this effect and each SNP after including the main SNP effect in the
model is reported.
Note the spaces between the variable names.