Conservation Genetics

, Volume 17, Issue 4, pp 839–846 | Cite as

Massive genetic introgression in threatened northern crested newts (Triturus cristatus) by an invasive congener (T. carnifex) in Western Switzerland

  • Christophe Dufresnes
  • Jérôme Pellet
  • Sandra Bettinelli-Riccardi
  • Jacques Thiébaud
  • Nicolas Perrin
  • Luca Fumagalli
Research Article


Genetic pollution through introgressive hybridization of local species by exotic relatives is a major, yet neglected aspect of biological invasions, particularly in amphibians where human introductions are frequent. In Western Switzerland, crested newts make an interesting case: the Italian species Triturus carnifex was introduced at least a century ago within the range of the native and threatened T. cristatus. To understand the genetic consequences of this introduction and inform wildlife management authorities, we conducted a genetic survey on the remaining northern crested newt populations known in the area, using newly-developed species-diagnostic nuclear (microsatellites) and mitochondrial (control region) DNA markers. We documented massive nuclear introgression by the T. carnifex genome, which has completely replaced T. cristatus in most populations, especially in the Geneva area where the introduction was originally reported. However, many of these individuals retained the ancestral T. cristatus mtDNA, which could be explained by asymmetric introgression between the two species, stemming from demographic and/or selective processes. Analyses of genetic diversity support multiple events of T. carnifex releases, most-likely of proximate North Italian origin. We pinpointed the last indigenous populations in the region and recommend to prioritize their protection. Our study demonstrates the invasive potential of introduced taxa through introgressive hybridization, alerts about the underestimated rate of illegal amphibian translocations, and emphasizes the need for genetic analyses to monitor such invasions.


Conservation Asymmetric reproductive isolation Hybridization Invasive species Amphibian Microsatellites mtDNA 

Supplementary material

10592_2016_825_MOESM1_ESM.pdf (60 kb)
Supplementary material 1 (PDF 60 kb)
10592_2016_825_MOESM2_ESM.pdf (145 kb)
Supplementary material 2 (PDF 144 kb)
10592_2016_825_MOESM3_ESM.pdf (328 kb)
Supplementary material 3 (PDF 328 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Christophe Dufresnes
    • 1
  • Jérôme Pellet
    • 2
  • Sandra Bettinelli-Riccardi
    • 1
  • Jacques Thiébaud
    • 3
  • Nicolas Perrin
    • 1
  • Luca Fumagalli
    • 1
  1. 1.Laboratory for Conservation Biology, Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
  2. 2.n+p Wildlife EcologyLausanneSwitzerland
  3. 3.KARCH-GE (Swiss Coordination Center for the Conservation of Amphibians and Reptiles—Geneva Regional Branch)GenevaSwitzerland

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