Two sides of the same coin? Transient hybridization in refugia and rapid postglacial ecological divergence ensure the evolutionary persistence of sister Nothofagus.

Autor:	Premoli AC; Universidad Nacional del Comahue, Centro Regional Universitario Bariloche-INIBIOMA CONICET, Bariloche, Argentina., Mathiasen P; Universidad Nacional del Comahue, Centro Regional Universitario Bariloche-INIBIOMA CONICET, Bariloche, Argentina., Acosta MC; Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.; Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina., McCulloch RD; School of GeoSciences, The University of Edinburgh, Edinburgh, Scotland.
Jazyk:	angličtina
Zdroj:	Journal of evolutionary biology [J Evol Biol] 2024 Oct 10; Vol. 37 (10), pp. 1181-1193.
DOI:	10.1093/jeb/voae100
Abstrakt:	Glacial periods have been considered as inhospitable environments that consist of treeless vegetation at higher latitudes. The fossil record suggests many species survived the Last Glacial Maximum within refugia, usually at lower latitudes. However, phylogeographic studies have given support to the existence of previously unknown high-latitude refugia that were not detected in the fossil record. Here, we test the hypothesis that cold-tolerant trees of Patagonia survived cold periods in microclimatically favourable locales where hybridization occurred between sister taxa. To study local presence through glacial periods in multiple refugia, we used pollen records and genetic information (isozymes, microsatellites, and combined nuclear and chloroplast DNA sequences) of population pairs of Nothofagus antarctica and N. pumilio that belong to the ancient subgenus Nothofagus which can potentially hybridize in nature, along their entire latitudinal range in Patagonia. Studied species share the N. dombeyi type pollen, which was abundant at >20% in the northernmost latitudinal bands (35-43°S), even during the Last Glacial Maximum. Mid- and southern latitudinal records (44-55°S) yielded lower abundances of ~10% that increased after c. 15.0 cal. ka BP. Therefore, fossil pollen evidence suggests a long-lasting local presence of Nothofagus throughout glacial-interglacial cycles but mostly as small populations between 44°S and 51°S. We found species-specific and shared genetic variants, the latter of which attained relatively high frequencies, thus providing evidence of ancestral polymorphisms. Populations of each species were similarly diverse, suggesting survival throughout the latitudinal range. Estimates of coalescent divergence times were broadly synchronous across latitudes, suggesting that regional climates similarly affected populations and species that hybridized through climate cycles, fostering local persistence. (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Evolutionary Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
Databáze:	MEDLINE
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