Appendix 1—Repeat sequences in putative gene PR.C
Ohno argued that removing a specific T nucleotide from gene RIIA (which codes for enzyme EII) leads to a putative predecessor gene PR.C having several short repeat sequences,1 such as those shown in tables 1–5.2 He claimed this showed that putative PR.C arose from a chain of identical oligomers.3
Ohno claimed the ancestral PR.C coded for a protein consisting of multiple copies of Arg-Arg-Arg-Ser-Thr-Pro-Leu-Asp-Ala-Ala, which we labelled AA-10 in this paper. He made no attempt to align such a protein with the product from PR.C to explain how the repeats in tables 1–5 could have subsequently arisen.
References and notes
- Ohno, S., Birth of a unique enzyme from an alternative reading frame of the pre-existed, internally repetitious coding sequence, Proc. Natl. Acad. Sci. USA 81:2421–2425, 1984. Return to text.
- See PR.C internal homology. Return to text.
- Yomo, T., Urabe, I. and Okada, H, No stop codons in the antisense strands of the genes for nylon oligomer degradation, Proc. Natl. Sci. USA 89:3780–3783, 1992. Return to text.