Before revision: Artificial peptide nucleic acids are capable forming duplex structures with individual DNA- and RNA-strands and are, therefore, not only called DNA-analog but also they are also considered as candidates for the first genetic material on Earth.
After revision: Artificial peptide nucleic acids are capable forming duplex structures with individual DNA- and RNA-strands and are, therefore, not only called DNA-analog but of, they are also considered as candidates for the first genetic material on Earth.