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 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,also not only called DNA-analog but they are also considered as candidates for the first genetic material on Earth.