Derivation-dependent Distribution of Insertion Sites for a Drosophila Transposon

An organism may not only be considered as an end product of a long evolution, but also as a mediator of the genetic material in the DNA molecules to the fol-lowing generations. The chromosomes haye to be trans-mitted to the next generation without any essential dam-age to their efficiency. This means that many gene mutations and especially large rearrangements, such as reciprocal translocations, will be discarded in the selec-, tive procedure that serves as a guard of continuity. For Drosophila, it also means that different species often have the same gene order in the homologous chromo-some arms. Most of the differences found have been ascribed to centric fusion of different arms and to peri-centric and paracentric inversions (Stone 1956). The small changes may have a better chance to be taken care