Letter | Published:

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

Naturevolume 351pages565568 (1991) | Download Citation



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 optionsAccess 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).

  2. 2

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

  3. 3

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

  4. 4

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

  5. 5

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

  6. 6

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

  7. 7

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

  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).

  10. 10

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

  11. 11

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

  12. 12

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

  13. 13

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

  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).

  15. 15

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

  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).

Download references

Author information

Author notes

    • S. M. Jenks

    Present address: Department of Psychology, University of California at Berkeley, Berkeley, California, 94720, USA


  1. Department of Biology, University of California at Los Angeles, Los Angeles, California, 90024, USA

    • R. K. Wayne
  2. Department of Physiology, University of California at San Francisco, San Francisco, California, 94143, USA

    • S. M. Jenks


  1. Search for R. K. Wayne in:

  2. Search for S. M. Jenks in:

About this article

Publication history



Issue Date



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.