The Distribution of log(D2cotinine/D2nicotine)(A) and D2cotinine/(D2cotinine+D2nicotine) (B) measured at time1 (t1, 30 minutes) among 189 European American subjects displayed as a cumulative histogram color-coded by diplotype class. White = normal/normal, Yellow = normal/intermediate, Green = intermediate/intermediate, Blue = normal/null, Purple = intermediate/null, Red = null/null. Normal haplotypes are *1A(51G),*1B, *1D,*1H and *14. Intermediate haplotypes are *1A(51A) and *9. Null haplotypes are *1D-Y351H, *2, *4 and *12. Genotype is not further differentiated.