This transgene, comprising the 310 kb human chr 11 YAC Y589 (from ICI library), retrofitted with a conditional centromere, was microinjected into pronuclei of B6CBA embryos. The YAC spans 160 kb upstream and 150 kb downstream of PAX6 promoter P1, a region that includes the SGL but not the SIMO breakpoints associated with cases of familial aniridia. Four transgenic lines were established, with line 2 carying an intact copy of the YAC. (J:265823)