A multiple chromosome rearrangement between chromosomes 2 and 3 has resulted in the P{GawB}cenB1A^Mai301 insertion being juxtaposed to the heterochromatin, causing mottled expression of the Scer\GAL4 and mini-w genes in the inserted element in the rearranged chromosome. The supposed new order is 21-40|49A- 41::94-100 and 61- 80::94-82 |50F-49AB|51-60 although the actual situation is somewhat more complicated and has not yet been clarified.