A suite of molecular markers for identifying species, detecting introgression and describing population structure in spadefoot toads (Spea spp.)

Authors

  • KARIN S. PFENNIG,

    1. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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  • ASHLEY ALLENBY,

    1. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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  • RYAN A. MARTIN,

    1. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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    • Present address: Department of Biology, North Carolina State University, Raleigh, NC 27695, USA.

  • ANAÏS MONROY,

    1. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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  • CORBIN D. JONES

    1. Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
    2. Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Karin Pfennig, Fax: 919-962-1625; E-mail: kpfennig@unc.edu

Abstract

Two congeneric species of spadefoot toad, Spea multiplicata and Spea bombifrons, have been the focus of hybridization studies since the 1970s. Because complex hybrids are not readily distinguished phenotypically, genetic markers are needed to identify introgressed individuals. We therefore developed a set of molecular markers (amplified fragment length polymorphism, polymerase chain reaction–restriction fragment length polymorphism and single nucleotide polymorphism) for identifying pure-species, F1 hybrids and more complex introgressed types. To do so, we tested a series of markers across both species and known hybrids using populations in both allopatry and sympatry. We retained those markers that differentiated the two pure-species and also consistently identified known species hybrids. These markers are well suited for identifying hybrids between these species. Moreover, those markers that show variation within each species can be used in conjunction with existing molecular markers in studies of population structure and gene flow.

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