Complex hybridization patterns in European pond turtles (Emys orbicularis) in the Pyrenean Region

• Published in: Scientific reports Vol. 8; no. 1; pp. 15925 - 13
• Main Authors: Pöschel, Julia, Heltai, Botond, Graciá, Eva, Quintana, Marc Franch, Velo-Antón, Guillermo, Arribas, Oscar, Valdeón, Aitor, Wink, Michael, Fritz, Uwe, Vamberger, Melita
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-10-2018; Nature Publishing Group
• Subjects: 45/22; 45/23; 631/181/457; 631/208/720; 631/601/2721; Bayesian analysis; Divergence; Emys orbicularis; Emys orbicularis galloitalica; Emys orbicularis occidentalis; Emys orbicularis orbicularis; Gene amplification; Genetic diversity; Genetic engineering; Holocene; Humanities and Social Sciences; Hybrid zones; Hybridization; Laboratories; Mitochondria; Mitochondrial DNA; multidisciplinary; Museums; Ponds; Science; Science (multidisciplinary); Speciation; Taxa; Taxonomy; Turtles; Zoology; Iberian Peninsula; Approximate Bayesian Computation; Admixed Population; Emys Orbicularis; Ebro Valley; Pond Turtle
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-34178-0

Hybrid zones are natural laboratories allowing insights in genetic processes like lineage diversification, speciation and introgression. Using large sampling, 15 microsatellite loci and a mitochondrial marker, we examined the Pyrenean contact zone of three pond turtle taxa (
Emys orbicularis orbicularis
,
E
.
o
.
galloitalica
,
E
.
o
.
occidentalis
). The Pyrenees are a biogeographically important region separating many lineages endemic to the Iberian Peninsula from their Western European counterparts. We discovered limited admixture, reflecting a complex biogeographic scenario. Simulations using Approximate Bayesian Computing supported that
E
.
o
.
orbicularis
invaded the Iberian Peninsula in the Holocene, circumventing the Pyrenees along the Mediterranean coast, and hybridized in the northern peninsula with the local coastal subspecies
galloitalica
, and to a lesser extent, with
occidentalis
. While
E
.
o
.
occidentalis
, and in particular
E
.
o
.
orbicularis
, expanded their ranges considerably during Holocene warming,
E
.
o
.
galloitalica
remained largely confined to its former Iberian refuge. Admixture among the three taxa is surprisingly low, and a future taxonomic investigation that includes the unstudied subspecies of
E
.
orbicularis
from North Africa, Eastern Europe and Asia has to determine whether their current status properly reflects their evolutionary divergence or whether certain taxa should be regarded as full species.