Add an option 'G.Model' to specify genetic model of "Add" (for additive), "Dom" (for dominant), or "Rec" (for recessive).
Subject IDs are required to check if genotype, environmental exposure and phenotypes share the same order. (Suggested by Alexander Rix)
SPAGE_0.1.5:
Update the package in case of errors from SPAtest:::Saddle_Prob(). The errors seem only happen for some rare variants. We ouput NA instead of pval-SPA. (Thank Lars G. Fritsche for pointing this out)