Figure 8: Compact and Extended Nucleic Acid Sequences. There are three categories of nucleic acid sequences. The oldest form is the compact sequence, in which codon boundaries cannot yet be recognized, so it is translated overlappingly (OTS). Extended OTS sequences developed from compact sequences and made it possible to read the OTS non-overlappingly. Extended non-OTS sequences are late developments and they cannot be compressed into compact forms. Codons are indicated by blue boxes. The difference between extended OTS and non-OTS is indicated by red letters. Note that the translation of extended OTS and non-OTS sequences into protein sequences is the same (yellow boxes).