Protein encoding by both DNA strands

All the evidence so far points to a gene's protein-coding information being contained in only one of its two DNA strands, with this strand serving as a template for transcription of the precursor RNA that is eventually translated into protein 1 . Here we present structural evidence showing that the protein-coding information of the modifier of mdg4 (mod(mdg4)) gene of the fruitfly Drosophila is provided by both of its complementary DNA strands, and not by just one. This novel organization means that RNA precursors generated from two DNA templates need to be joined subsequently into a single messenger RNA, a surprising feature that raises new questions regarding genome complexity and evolution.