Range dynamics driven by Quaternary climate oscillations explain the distribution of introgressed mtDNA of Lepus timidus origin in hares from the Iberian Peninsula
[Aim]: A striking case of mitochondrial DNA (mtDNA) introgression occurs in the Iberian Peninsula: the mtDNA of Lepus timidus, a species that inhabited this territory during the Last Glacial Maximum (LGM), is almost fixed in the Iberian range of Lepus europaeus, is very frequent in the northern half of Iberia within Lepus granatensis, and is fixed in Lepus castroviejoi. Here, we used a transdisciplinary approach to understand the ecological drivers of the distribution of this introgressed mtDNA in the Iberian hare species. [Location]: Europe, with an emphasis on the Iberian Peninsula. [Methods]: First, we modelled the climatic niche of L. timidus to predict the favourability for the species during the LGM. Second, we gathered data regarding L. timidus mtDNA introgression for 1137 individuals (139 populations) from the Iberian Peninsula. We tested whether the climatic favourability for L. timidus during the LGM reflects the frequency of the introgressed mtDNA in the carrier hare populations. [Results]: The climatic favourability for the LGM is positively related to the presence of individuals with L. timidus mtDNA, and discriminates better than by chance between individuals with and without this lineage. At the population level, the favourability values relate to the observed frequencies of mtDNA introgression and discriminate between populations with and without L. timidus mtDNA. [Main conclusions]: The results suggest that the geographical distribution of L. timidus mtDNA introgression is linked to L. timidus distribution in Iberia during the LGM. Our study helps to improve our understanding of the role of climate in the reticulated evolutionary history of hares, and is a first step towards understanding the ecological impact of mtDNA introgression on Iberian hares.P.A. is currently supported by the Spanish Ministerio de Economía y Competitividad (MINECO) and Universidad de Castilla-La Mancha (UCLM) through a ‘Ramón y Cajal’ contract (RYC-2012-11970). J.M.-F. and R.C. hold FCT Investigator and postdoctoral grants, respectively, from the Fundaçao para a Ciência e a Tecnologia (FCT), funded by Programa Operacional Potencial Humano (POPH) – Quadro de Referencia Estrategico Nacional (QREN) from the European Social Fund and by the Portuguese Ministerio da Educacao e Ciencia (IF/00033/2014 and SFRH/BPD/64365/2009, respectively). This work is funded by FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE and by National Funds through FCT – Foundation for Science and Technology under the EXPL/AAG-MAA/1082/2013 and FCOMP-01-0124-FEDER-041082. Partial funding was also obtained from FCT-ANR/BIA-EVF/0250/2012 and by the Spanish Ministry of Agriculture, Food and Environment, Spanish National Park’s Network (project 1098/2014).Peer Reviewe
