Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. 1994 Aug 2; 91(16): 7506–7509.

Evidence for intron capture: an unusual path for the evolution of proteins.


Most new genes are thought to evolve from preexisting genes but duplications of entire genes or shuffling of preexisting exons provides only a limited repertoire of new sequences that can be presented to a cell. Only pieces that previously existed can be used in the construction and any further divergence depends on the slow accumulation of mutations. We show here the presence of a small, in-frame intron in a ciliate phosphoglycerate kinase gene and the insertion of an unusually random amino acid sequence at the same position in trypanosome phosphoglycerate kinase. The unusual sequences in trypanosomes were likely to have originally been introns that have been subsequently captured by the protein and have now been incorporated as part of the coding sequence. Via this path a truly unique sequence can be incorporated into an existing protein, leading in time to the evolution of a new, functionally distinct protein.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (804K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Gilbert W. Why genes in pieces? Nature. 1978 Feb 9;271(5645):501–501. [PubMed]
  • Gilbert W. The exon theory of genes. Cold Spring Harb Symp Quant Biol. 1987;52:901–905. [PubMed]
  • Dorit RL, Schoenbach L, Gilbert W. How big is the universe of exons? Science. 1990 Dec 7;250(4986):1377–1382. [PubMed]
  • Ohno S. Original domain for the serum albumin family arose from repeated sequences. Proc Natl Acad Sci U S A. 1981 Dec;78(12):7657–7661. [PMC free article] [PubMed]
  • Blake C. Exons--present from the beginning? Nature. 1983 Dec 8;306(5943):535–537. [PubMed]
  • Smith MW, Feng DF, Doolittle RF. Evolution by acquisition: the case for horizontal gene transfers. Trends Biochem Sci. 1992 Dec;17(12):489–493. [PubMed]
  • Go M, Nosaka M. Protein architecture and the origin of introns. Cold Spring Harb Symp Quant Biol. 1987;52:915–924. [PubMed]
  • Cavalier-Smith T. Selfish DNA and the origin of introns. Nature. 1985 May 23;315(6017):283–284. [PubMed]
  • Südhof TC, Goldstein JL, Brown MS, Russell DW. The LDL receptor gene: a mosaic of exons shared with different proteins. Science. 1985 May 17;228(4701):815–822. [PubMed]
  • Ohno S. Birth of a unique enzyme from an alternative reading frame of the preexisted, internally repetitious coding sequence. Proc Natl Acad Sci U S A. 1984 Apr;81(8):2421–2425. [PMC free article] [PubMed]
  • Butticè G, Kaytes P, D'Armiento J, Vogeli G, Kurkinen M. Evolution of collagen IV genes from a 54-base pair exon: a role for introns in gene evolution. J Mol Evol. 1990 Jun;30(6):479–488. [PubMed]
  • Dente L, Cesareni G, Cortese R. pEMBL: a new family of single stranded plasmids. Nucleic Acids Res. 1983 Mar 25;11(6):1645–1655. [PMC free article] [PubMed]
  • Sanger F, Nicklen S, Coulson AR. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. [PMC free article] [PubMed]
  • Staden R. Searching for patterns in protein and nucleic acid sequences. Methods Enzymol. 1990;183:193–211. [PubMed]
  • Don RH, Cox PT, Wainwright BJ, Baker K, Mattick JS. 'Touchdown' PCR to circumvent spurious priming during gene amplification. Nucleic Acids Res. 1991 Jul 25;19(14):4008–4008. [PMC free article] [PubMed]
  • Vohra GB, Golding GB, Tsao N, Pearlman RE. A phylogenetic analysis based on the gene encoding phosphoglycerate kinase. J Mol Evol. 1992 May;34(5):383–395. [PubMed]
  • Dupuis P. The beta-tubulin genes of Paramecium are interrupted by two 27 bp introns. EMBO J. 1992 Oct;11(10):3713–3719. [PMC free article] [PubMed]
  • Alexander K, Parsons M. A phosphoglycerate kinase-like molecule localized to glycosomal microbodies: evidence that the topogenic signal is not at the C-terminus. Mol Biochem Parasitol. 1991 May;46(1):1–10. [PubMed]
  • Le Blancq SM, Swinkels BW, Gibson WC, Borst P. Evidence for gene conversion between the phosphoglycerate kinase genes of Trypanosoma brucei. J Mol Biol. 1988 Apr 5;200(3):439–447. [PubMed]
  • Swinkels BW, Evers R, Borst P. The topogenic signal of the glycosomal (microbody) phosphoglycerate kinase of Crithidia fasciculata resides in a carboxy-terminal extension. EMBO J. 1988 Apr;7(4):1159–1165. [PMC free article] [PubMed]
  • Saitou N, Nei M. The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol. 1987 Jul;4(4):406–425. [PubMed]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences


Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • MedGen
    Related information in MedGen
  • PubMed
    PubMed citations for these articles
  • Substance
    PubChem Substance links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...