Transcription according to DHFR genotypes and haplotypes. (A) DHFR haplotype's promoter strength relative to blank (Gateway-adapted pGL3-basic vector). Haplotypes *3, *4, *1, and *5 are represented by dark gray, light gray, white, and black bars, respectively. The relative values are given for 3 different cell lines: HeLa, Jeg-3, and HepG2. *Haplotypes showing significant increase in transcription (P < .01, Student t test) when compared with haplotype 3 or to haplotype 4. Tables illustrate relative promoter activity (values and standard deviation) for each haplotype as well as ratio of relative promoter activity between haplotypes with high and low expression. (B) Relative mRNA levels according to DHFR genotypes and haplotypes. The mean value of expression with 95% CI, the number of individuals represented by each line, and P value obtained by Mann-Whitney test (CC −1610 genotype) and ANOVA (*1*1 and *1*3 haplotype pairs) for the difference of expression between carriers (+) and noncarriers (−) of indicated genotypes/haplotypes are indicated on the plots.