Conservation Genetics

, 7:483 | Cite as

The endangered Sonoran topminnow: Examination of species and ESUs using three mtDNA genes



There has been controversy over the species status of Sonoran topminnows and debate about the presence of ESUs in the Gila topminnow. From examination of sequence variation at 2626 base pairs over three mtDNA genes, we found a 29 (1.1%) nucleotide genetic difference between Gila and Yaqui topminnows. This provides strong support that these two taxa are separate species, Poeciliopsis occidentalis (Gila topminnow) and P. sonoriensis (Yaqui topminnow) and have been separated for approximately one million years. All the Gila topminnows within Arizona have the same sequence for the three mtDNA genes, that is, there is not reciprocal monophyly for mtDNA sequence data for the two previously designated ESUs. However, evidence of the unique habitat for Monkey Spring, its long-term isolation from other Gila topminnow habitats, and the presence of unique fish and invertebrate taxa in Monkey Spring support the designation of the Monkey Spring topminnows as an ESU. Finally, theoretical considerations using molecular data and estimates of heterozygosity and genetic distance for nuclear genes between populations of the Gila topminnow show that the lack of mtDNA variation is not inconsistent with the level and pattern of nuclear genetic variation observed.

Key words:

ESU effective population size genetic distance mtDNA Poeciliopsis 



We appreciate the financial support from the Arizona Heritage Fund and the Ullman Professorship for this research. We appreciate comments on an earlier version of this manuscript from two anonymous reviewers.


  1. Bermingham E, McCafferty SS, Martin AP (1997) Fish biogeography and molecular clocks: perspectives from the Panamanian Isthmus. In: Kocher TD, Stepien CA (eds). Molecular Systematics of Fishes. Academic, San Diego, pp. 113–128CrossRefGoogle Scholar
  2. Broughton RE, Milam JE, Roe BA (2001). The complete sequence of the zebrafish (Danio rerio) mitochondrial genome and evolutionary patterns in vertebrate mitochondrial DNA. Genome Res. 11:1958–67PubMedGoogle Scholar
  3. Cardwell T, Sheffer RS, Hedrick PW (1998) Male development in the endangered Gila topminnow. J. Hered. 89:353–355CrossRefGoogle Scholar
  4. Chakraborty R, Nei M (1977) Bottleneck effects on average heterozygosity and genetic distance with the stepwise mutation model. Evolution 31:347–356CrossRefGoogle Scholar
  5. Coyne JA, Orr HA (1989) Patterns of speciation in Drosophila. Evolution 43:362–381CrossRefGoogle Scholar
  6. Crandall KA, Bininda-Emonds ORP, Mace GM, Wayne RK (2000) Considering evolutionary processes in conservation biology. Trends Ecol. Evol. 15:290–295PubMedCrossRefGoogle Scholar
  7. Dowling TE, Tibbetts AC, Minckley WL, Smith GR (2002) Evolutionary relationships of the Plagopterins (Teleostei: Cyprinidae) from Cytochrome b sequences. Copeia 2002:665–678CrossRefGoogle Scholar
  8. Fraser DJ, Bernatchez L (2001) Adaptive evolutionary conservation: towards a unified concept for defining conservation units. Molec. Ecol. 10:2741 2752PubMedGoogle Scholar
  9. Glavac DM, Dean M (1993). Optimization of the Single-Strand Conformation Polymorphism (SSCP) technique for detection of point mutations. Hum. Mut. 2:404–414PubMedCrossRefGoogle Scholar
  10. Hall T (1991–2004) BioEdit Sequence Alignment Editor. Isis Pharmaceuticals, IncGoogle Scholar
  11. Hedrick PW (1999) Perspective: highly variable loci and their interpretation in evolution and conservation. Evolution 53:313–318CrossRefGoogle Scholar
  12. Hedrick PW (2005) Genetics of Populations, 3rd Edition. Jones and Bartlett, BostonGoogle Scholar
  13. Hedrick PW, Parker KM (1998) MHC variation in the endangered Gila topminnow. Evolution 52:194–199CrossRefGoogle Scholar
  14. Hedrick PW, Parker KM, Lee R (2001) Genetic variation in the endangered Gila and Yaqui topminnows: microsatellite and MHC variation. Molec. Ecol. 10:1399–1412PubMedCrossRefGoogle Scholar
  15. Hughes J, Ponniah M, Harwood D, Chenoweth S, Arthington A (1999) Strong genetic structuring in a habitat specialist, the Oxleyan Pygmy Perch Nannopera oxleyana. Heredity 83:5–14PubMedCrossRefGoogle Scholar
  16. Hurt, CR (2004) Genetic divergence, population structure and historical demography of rare springsnails (Pyrgulopsis) in the lower Colorado River basin. Molec. Ecol. 13:1173–1187PubMedCrossRefGoogle Scholar
  17. Hurt CR, Stears-Ellis S, Hughes K, Hedrick PW (2004) Mating behavior in the endangered Sonoran topminnow: speciation in action. Anim. Behav. 67:343–351CrossRefGoogle Scholar
  18. Hurt CR, Hedrick PW (2003) Initial stages of reproductive isolation in two species of the endangered Sonoran topminnow. Evolution 57:2835–2841PubMedGoogle Scholar
  19. Hurt CR, Farzin M, Hedrick PW (2005) Premating, not postmating, barriers drive genetic dynamics in experimental hybrid populations of the endangered sonaran topminnow. Genetics, in pressGoogle Scholar
  20. Kumar S (1996) PHYLTEST: Phylogenetic hypothesis testing software. Version 2.0. Pennsylvania State University, University Park, PennsylvaniaGoogle Scholar
  21. Kumar S, Tamura K, Jakobsen IB, Nei M (2001) MEGA2: Molecular Evolutionary Genetics Analysis software. Arizona State University, Tempe, ArizonaGoogle Scholar
  22. Li WH (1976) Electrophoretic identity of proteins in a finite population and genetic distance between taxa. Genet. Res. 28:119–127PubMedCrossRefGoogle Scholar
  23. Mateos M, Sanjur OI, Vrijenhoek RC (2002) Historical biogeography of the livebearing fish genus Poeciliopsis (Poeciliidae: Cyprinodontiformes). Evolution 56:972–984PubMedGoogle Scholar
  24. Melton MA (1960) Origin of the drainage of southeastern Arizona. AZ. Geol. Soc. Digest 3:113–122Google Scholar
  25. Minckley WL (1973) Keys to native and introduced fishes of Arizona. J. Ariz. Acad. Sci. 6:183–188Google Scholar
  26. Minckley WL (1999) Ecological review and management recommendation for recovery of the endangered Gila topminnow. Great Basin Natur. 59:230–244Google Scholar
  27. Moritz C (1994) Defining “evolutionarily significant units” for conservation. Trends Ecol. Evol. 9:373–375CrossRefGoogle Scholar
  28. Moritz C (2002) Strategies to protect biological diversity and the evolutionary processes that sustain it. Syst. Biol. 51:238–254PubMedCrossRefGoogle Scholar
  29. Nei M (1987) Molecular Evolutionary Genetics. Columbia University Press, New YorkGoogle Scholar
  30. Parker KM, Sheffer RJ, Hedrick PW (1999) Molecular variation and evolutionarily significant units in the endangered Gila topminnow. Cons. Biol. 13:108–116CrossRefGoogle Scholar
  31. Quattro JM, Leberg PL, Douglas ME, Vrijenhoek RC (1996) Molecular evidence for a unique evolutionary lineage of endangered Sonoran desert fish (genus Poeciliopsis). Cons. Biol. 10:128–135CrossRefGoogle Scholar
  32. Sheffer RJ, Hedrick PW, Velasco AL (1999) Testing for inbreeding and outbreeding depression in the endangered Gila topminnow. Anim. Cons. 2:121–129CrossRefGoogle Scholar
  33. Stepine CA, Dillion AK, Brooks MJ, Chase KL, Hubers AN (1997) The evolution of blennioid fishes based on an analysis of mitochondrial 12S rDNA. In: Kocher TD, Stepien CA (eds). Molecular Systematics of Fishes. Academic, San Diego, pp. 245–270CrossRefGoogle Scholar
  34. Takezaki N, Razhetsky A, Nei M (1995) Phylogenetic test of the molecular clock and linearized trees. Mol. Biol. Evol. 12:823–833PubMedGoogle Scholar
  35. Vrijenhoek RC, Douglas ME, Meffe GK (1985) Conservation genetic of endangered fish populations in Arizona. Science 229:400–402PubMedCrossRefGoogle Scholar
  36. Waples RS (1995) Evolutionarily significant units and the conservation of biological diversity under the Endangered Species Act. Amer. Fish. Soc. Symp. 17:8–27Google Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  1. 1.School of Life SciencesArizona State UniversityTempeUSA

Personalised recommendations