The elevated X and fourth chromosome nondisjunction seen in In(1)FM7/X ; svspa-pol females heterozygous for mtrmKG08051 is largely rescued by expression of mtrmScer\UAS.P\T.cHa under the control of Scer\GAL4nos.UTR.T:Hsim\VP16; the rescued females show only 2.7% X and 7.1% fourth chromosome nondisjunction.