Mutation in sequenced strain: deletion (-23).
There is a 23 base deletion in CG43092 in iso-1, the reference sequence strain relative to similar sequences in Dsim and Dsec. 23 bases between 3R:22769523 and 22769524 in iso-1 would be needed to encode the missing amino acids. This leads to a frameshift after codon 25 and early translation termination.