Mitochondrial DNA analysis implying extensive hybridization of the endangered red wolf Canis rufus


THE red wolf, previously endemic to the southeastern United States, declined precipitously in numbers after 1900 because of habitat destruction, predator control programmes, and hybridiz-ation with coyotes1,2. Hybridization with coyotes probably occurred as these animals, which adjust well to agriculture, became numerous and moved eastwards1–4. By 1970, red wolves existed only in extreme southeastern Texas and southwestern Louisana (Fig. 1)2. In 1967, red wolves were classified as endangered and a captive breeding programme was begun in 1974 after passage of the Endangered Species Act, about a year before they became extinct in the wild. Protein electrophoresis and morphometrics have been used to try to discriminate red wolves from hybrids and coyotes1,4,5. But because the average substitution rate of mitochondrial DNA in mammals is much greater than that of nuclear genes6, mtDNA analysis is a more useful way of distinguishing closely related species. We have now analysed mtDNA restriction-enzyme sites and cytochrome b gene sequence variation in captive red wolves and in 77 canids sampled during the capture period. We also used the polymerase chain reaction to amplify and then sequenced mtDNA from red wolf skins collected before substantial hybridization of red wolves with coyotes is thought to have occurred. Phylogenetic analysis indicates that red wolves have either a grey wolf or coyote mtDNA genotype, demonstrating hybridization among these species. Thus, the red wolf is entirely a hybrid form or a distinct taxon that hybridized with coyotes and grey wolves over much of its previous geographical range. Our findings, however, do not argue against the continued protection of the red wolf.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Nowak, R. M. North American Quaternary Canis (Mongr. Mus. Nat. Hist. Univ. Kansas, Lawrence,1979).

    Google Scholar 

  2. 2

    McCarley, H. Southwestern Naturalist 7, 227–235 (1962).

    Article  Google Scholar 

  3. 3

    Young, S. P. The Wolves of North America (Dover, New York, 1944).

    Google Scholar 

  4. 4

    Lawrence, B. & Bossert, W. H. Am. Zool. 7, 223–232 (1967).

    Article  Google Scholar 

  5. 5

    Ferrell, R. E. et al. Biochem. Genet. 18, 39–49 (1980).

    CAS  Article  Google Scholar 

  6. 6

    Brown, W. M., George, M. & Wilson, A. C. Proc. natn. Acad. Sci. U.S.A. 76, 1967–1971 (1979).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Lehman, N. et al. Evolution 45, 104–119 (1991).

    Article  Google Scholar 

  8. 8

    Lehman, N. & Wayne, R. K. Genetics (in the press).

  9. 9

    Wayne, R. K. et al. Proc. natn. Acad. Sci. U.S.A. 87, 1772–1776 (1990).

    ADS  CAS  Article  Google Scholar 

  10. 10

    Meyer, A. & Wilson, A. C. J. molec. Evol. 31, 359–370 (1990).

    ADS  CAS  Article  Google Scholar 

  11. 11

    Felsenstein, J. Evolution 39, 783–791 (1985).

    Article  Google Scholar 

  12. 12

    Mech, L.D. The Wolf: The Ecology and Behavior of an Endangered Species (University of Minnesota, Minneapolis, 1970).

    Google Scholar 

  13. 13

    Barton, N. H. & Hewitt, G. M. Nature 341, 497–503 (1989).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Mech, D. L. in Mammalian Dispersal Patterns (eds Chepko-Sade, B. D. & Halpin, Z. T.) 55–74 (University of Chicago Press, Chicago, 1987).

    Google Scholar 

  15. 15

    Gyllensten, U. B. & Erlich, H. A. Proc. natn. Acad. Sci. U.S.A. 85, 7652–7656 (1988).

    ADS  CAS  Article  Google Scholar 

  16. 16

    Carbyn, L. N. Gray Wolf and Red Wolf (eds Novak, M., Baker, J. A., Obbard, M. E. & Malloch, B.) 358–377 (Ontario Ministry of Natural Resources, Toronto, 1987).

    Google Scholar 

Download references

Author information



Rights and permissions

Reprints and Permissions

About this article

Cite this article

Wayne, R., Jenks, S. Mitochondrial DNA analysis implying extensive hybridization of the endangered red wolf Canis rufus. Nature 351, 565–568 (1991).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing