“…Each DNA molecule is thought to represent a transcription and replication unit and consists of a single intronless coding region flanked by short (74 bp to 1000 bp) AT-rich (75%-80%) noncoding sequences terminating in telomeric inverted repeats of C4A4. The coding regions show, like those of some other ciliates, an altered genetic code using the "universal" stop codons TAA and TAG to specify glutamine [8,10,18,19,22,25,36,40].…”