Gymnastics is a unique sport in the college sports landscape. There are only 81 NCAA gymnastics programs with 62 competing at the Division I level. Because of the relatively small number of teams, DI teams regularly compete against DII and DIII teams during the regular season.
The small number of teams also means that some conferences have affiliate programs that only compete in that sport. The Big 12 is one of those conferences. The University of Denver competes in Big 12 gymnastics.
There are no DI gymnastics teams in Texas despite the large number of elite gymnasts that come from that state.