INTERSPECIFIC X-CHROMOSOME AND MITOCHONDRIAL DNA INTROGRESSION IN THE IBERIAN HARE: SELECTION OR ALLELE SURFING?

• Published in: Evolution
• Main Authors: Melo-Ferreira, José, Alves, Paulo, C., Rocha, Jorge, Ferrand, Nuno, Boursot, Pierre
• Other Authors: Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO-UP), Universidade do Porto = University of Porto-CESPU, Centro de Investigacao em Biodiverdidade e Recursos Geneticos (CIBIO-UP), Universidade do Porto = University of Porto, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Ctr Invest Biodiversidade & Recursos Genet - CIBIO InBIO, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Lepus granatensis; Lepus timidus; invasion; hybridization; glaciation; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; Arctic hare; Arctic
• Online Access: https://hal.umontpellier.fr/hal-02347849; https://hal.umontpellier.fr/hal-02347849/document; https://hal.umontpellier.fr/hal-02347849/file/j.1558-5646.2011.01261.x.pdf; https://doi.org/10.1111/j.1558-5646.2011.01261.x

International audience Introgression from a resident species into an invading one is predicted to occur through the demographic process of "allele surfing," and to particularly affect genomic regions transmitted by the lower migrating sex, such as mtDNA. This could explain that northern Iberian populations of Lepus granatensis harbor high frequencies of mtDNA from L. timidus, an arctic hare it replaced there after deglaciation. We report that variation of introgressed timidus-like mtDNA reflects several predicted effects of this process: increasing frequency and diversity in the direction of expansion, strong perpendicular phylogeographic structure and signs of postglacial demographic growth. However, demographic inferences for the granatensis and timidus-like mtDNA lineages suggest the latter may have outcompeted the former in northern Iberia. Autosomal introgression occurs at low frequencies and species-wide rather than only in the north. If this difference with mtDNA resulted from sex-biased migration, an intermediate pattern should prevail for the X-chromosome, but we report species-wide and high-frequency introgression of an X-fragment. Either selection favored this ubiquitous X-introgression, or more complex postglacial expansion patterns prevailed, with different consequences depending on the genomic and geographic region. This illustrates the difficulty of distinguishing demographic and selective effects and the need for genome and species-wide based demographic models.