Past climate changes facilitated homoploid speciation in three mountain spiny fescues (Festuca, Poaceae).
Apart from the overwhelming cases of allopolyploidization, the impact of speciation through homoploid hybridization is becoming more relevant than previously thought. Much less is known, however, about the impact of climate changes as a driven factor of speciation. To investigate these issues, we selected Festuca picoeuropeana, an hypothetical natural hybrid between the diploid species F. eskia and F. gautieri that occurs in two different mountain ranges (Cantabrian Mountains and Pyrenees) separated by more than 400 km. To unravel the outcomes of this mode of speciation and the impact of climate during speciation we used a multidisciplinary approach combining genome size and chromosome counts, data from an extensive nuclear genotypic analysis, plastid sequences and ecological niche models (ENM). Our results show that the same homoploid hybrid was originated independently in the two mountain ranges, being currently isolated from both parents and producing viable seeds. Parental species had the opportunity to contact as early as 21000 years ago although niche divergence occurs nowadays as result of a climate-driven shift. A high degree of niche divergence was observed between the hybrid and its parents and no recent introgression or backcrossed hybrids were detected, supporting the current presence of reproductive isolation barriers between these species.
Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, C/Carretera de Cuarte Km 1, E22071 Huesca, Spain.
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Marques
Centro de Ecologia, Evolução e Alterações Ambientais (CE3C - Centre for Ecology, Evolution and Environmental Changes), C2, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal.
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Draper
Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, C/Carretera de Cuarte Km 1, E22071 Huesca, Spain.
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López-Herranz
Institut Botànic de Barcelona (IBB-CSIC-ICUB), Passeig del Migdia s/n, 08038 Barcelona, Spain.
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Garnatje
Departamento de Biología Vegetal, Facultad de Ciencias Biológicas, Universitat de València, Avda. Dr. Moliner, 50, E-46100, Burjassot, Spain.
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Segarra-Moragues
Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, C/Carretera de Cuarte Km 1, E22071 Huesca, Spain.|Department of Botany, Institute of Biology, Tomsk State University, Lenin Av. 36, 634050 Tomsk, Russia.
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Catalán
D057231:Climate Change; D004171:Diploidy; D031751:Festuca / Q000145:classification / Q000235:genetics*; D049810:Genetic Speciation; D014644:Genetic Variation; D018745:Genome, Plant / Q000235:genetics; D005843:Geography; D006824:Hybridization, Genetic; D010802:Phylogeny; D011003:Ploidies; D011123:Polyploidy; D060047:Reproductive Isolation; D013030:Spain; D013045:Species Specificity