The intronic 19911A>G polymorphism affects splicing. Clones containing the 19911G base have an on average 31% higher ratio of spliced mRNA compared with those containing the 19911A base (P < .05) as judged by their relative luciferase (luc) activity per β-galactosidase (β-gal) activity output. There were 6 experiments performed in duplicate. Error bars represent the standard error of mean. The left column is used for normalization and has no error bar.