Decrease of proportion of complete duplicated new genes with time. (D. mel) D. melanogaster, (D. sch) D. sechellia, (D. sim) D. simulans. These three species together stand for the D. melanogaster species complex. We compared structures and lengths of parental and new genes in D. melanogaster and the D. melanogaster species complex. New genes completely duplicating their ancestors’ coding regions seem more vulnerable to subsequent loss or structure changes during evolution.