Long-Range Cis Preference in DNA Homology Search Over the Length of a Drosophila Chromosome

Abstract
P element-induced chromosome breakage on the X chromosome of Drosophila melanogaster was repaired six times more frequently when a homologous template was located anywhere on the X chromosome rather than on an autosome. Cis-trans comparisons confirmed that recombinational repair was more frequent when the interacting sequences were physically connected. These results suggest that the search for homology between the broken ends and a matching template sequence occurs preferentially in the cis configuration. This cis advantage operates over more than 15 megabases of DNA.