Homozygous Top3α^B9-2 mutant eyes show moderate defects in compensatory growth in response to tissue loss (induced by generating larval clones of the temperature-sensitive cell-lethal mutation sec5^ts1 under the control of Scer\GAL4^en-e16E at the restrictive temperature). The resulting eyes are smaller than wild type. Moderate defects in cell proliferation are also detected when the sec5^ts1 cells are not ablated (i.e. when the flies are maintained at the permissive temperature). The proportion of mutant eye tissue seen following generation of wild type non-ablating clones is similar at 25[o]C and 30[o]C suggesting the mutation is not temperature sensitive. Top3α^B9-2 mutant eyes show moderate growth defects when tissue is ablated during the larval stages using irradiation.