Pi phenotypes in North American workers: racial differences and comparisons with reported frequencies.

The distribution of Pi phenotypes among Caucasian and Asian workers in British Columbia, Canada were found to differ significantly. Among Caucasians the frequency of the M allele was 0.9428, very similar to frequencies reported in other North American Caucasian populations. Among Asians only the M allele was found, further confirming the rarity of other alleles in such populations. The distribution of phenotypes in the Caucasian population agreed with the predictions of the Hardy-Weinberg law.