When Gregor Mendel figured out the inheritance patterns of dominant and recessive genes while studying pea plants, he began to crack a code. Dominant genes were shown as capital letters, maybe representing two brown-eyed parents having a brown-eyed kid. Easy enough (especially since pea plants don't have eyes), but then there are confounding mathematics and these mysterious things called proofs: odd symbols and cryptic-sounding half-sentences that ultimately confirm some sort of conclusion. Yawn. But don't go to sleep just yet even though Proof is a play about both genetics and math, there's more to this story. Catherine's father was once a brilliant mathematician, but his capacities devolved into psychosis before his death, leaving her to wonder if she inherited her father's genius or his madness. The drama unfolds when Proof opens at the Alton Little Theater (2450 North Henry Street, Alton, Illinois) on Friday, January 20, at 8 p.m. (the play is presented at 2 p.m. on Sundays). Tickets are $6 to $12; call 618-462-6562 for more information, and visit www.altonlittletheater.org for other performance dates (Proof closes on Sunday, January 29).