<qa>  What is the 16th amino-acid position of the -2 adrenParticipants were homozygous for arginine or glycine at the 16th amino-acid position of the β-2 adrenergic receptor B16 ArgArg or B16 GlyGly. Individuals were matched against their opposite genotype by forced expiratory volume in one second FEV1 and race. Matched participants entered an 8-week run-in period. This is a 62-week crossover design where subjects receive the following therapies: 