Directing the outcome of deoxyribozyme selections to favor native 3'-5' RNA ligation

The results related to natural selection, in which abrupt environmental variation can provide a rapid change in selection pressure. The new approach to obtain 3'-5' selective RNA ligase deoxyribozymes is particularly important for ongoing selection efforts. Linear 3'-5' RNA linkages are an important practical objective because the native backbone is desirable in site-specifically modified ribozymes assembled by ligation.