Bioorthogonal information storage in l-DNA with a high-fidelity mirror-image Pfu DNA polymerase

Natural DNA is exquisitely evolved to store genetic information. The chirally inverted l -DNA, possessing the same informational capacity but resistant to biodegradation, may serve as a robust, bioorthogonal information repository. Here we chemically synthesize a 90-kDa high-fidelity mirror-image Pfu DNA polymerase that enables accurate assembly of a kilobase-sized mirror-image gene. We use the polymerase to encode in l -DNA an 1860 paragraph by Louis Pasteur that first proposed a mirror-image world of biology. We realize chiral steganography by embedding a chimeric d -DNA/ l -DNA key molecule in a d -DNA storage library, which conveys a false or secret message depending on the chirality of reading. Furthermore, we show that a trace amount of an l -DNA barcode preserved in water from a local pond remains amplifiable and sequenceable for 1 year, whereas a d -DNA barcode under the same conditions could not be amplified after 1 day. These next-generation mirror-image molecular tools may transform the development of advanced mirror-image biology systems and pave the way for the realization of the mirror-image central dogma and exploration of their applications.