In(3LR)bxd194L79iR (FBab0023878) and In(3LR)79iLbxd194R (FBab0023871) are reciprocal recombinant chromosomes generated by meiotic recombination within the regions inverted in In(3LR)bxd194 (FBab0022902) and In(3LR)79i (FBab0005361). Craymer determined the breakpoints of In(3LR)79i to be 67B11-67C1;87D5-87D13 in FBrf0063387 and the breakpoints of In(3LR)bxd194 to be 80;89E in FBrf0036539. Given this information, In(3LR)bxd194L79iR should have two duplicated segments (67B11-67C1;80 and 87D5-13;89E) and look something like this: 3Lt--80|89E--67C1|87D5--3Rt and In(3LR)79iLbxd194R should should have two deleted segments (67B11-67C1;80 and 87D5-13;89E) and look something like this: 3Lt--67C1|87D5--80|89E--3Rt In fact, these two chromosomes are probably more complicated, because FBrf0144895 reported that In(3LR)bxd194 is likely a complex rearrangement. Kevin -- Kevin Cook, Ph.D. Bloomington Drosophila Stock Center Department of Biology Indiana University