The role of multiple Pleistocene refugia in promoting diversification in the Pacific Northwest.

Autor: Smith ML; Department of Evolution, Ecology & Organismal Biology, The Ohio State University, Columbus, Ohio, USA., Wallace J; Department of Evolution, Ecology & Organismal Biology, The Ohio State University, Columbus, Ohio, USA., Tank DC; Department of Botany and Rocky Mountain Herbarium, University of Wyoming, Laramie, Wyoming, USA.; Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA.; Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, Idaho, USA., Sullivan J; Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA.; Biological Sciences, Institute for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, Idaho, USA., Carstens BC; Department of Evolution, Ecology & Organismal Biology, The Ohio State University, Columbus, Ohio, USA.
Jazyk: angličtina
Zdroj: Molecular ecology [Mol Ecol] 2022 Aug; Vol. 31 (16), pp. 4402-4416. Date of Electronic Publication: 2022 Jul 17.
DOI: 10.1111/mec.16595
Abstrakt: Pleistocene glacial cycles drastically changed the distributions of taxa endemic to temperate rainforests in the Pacific Northwest, with many experiencing reduced habitat suitability during glacial periods. In this study, we investigate whether glacial cycles promoted intraspecific divergence and whether subsequent range changes led to secondary contact and gene flow. For seven invertebrate species endemic to the PNW, we estimated species distribution models (SDMs) and projected them onto current and historical climate conditions to assess how habitat suitability changed during glacial cycles. Using single nucleotide polymorphism (SNP) data from these species, we assessed population genetic structure and used a machine-learning approach to compare models with and without gene flow between populations upon secondary contact after the last glacial maximum (LGM). Finally, we estimated divergence times and rates of gene flow between populations. SDMs suggest that there was less suitable habitat in the North Cascades and Northern Rocky Mountains during glacial compared to interglacial periods, resulting in reduced habitat suitability and increased habitat fragmentation during the LGM. Our genomic data identify population structure in all taxa, and support gene flow upon secondary contact in five of the seven taxa. Parameter estimates suggest that population divergences date to the later Pleistocene for most populations. Our results support a role of refugial dynamics in driving intraspecific divergence in the Cascades Range. In these invertebrates, population structure often does not correspond to current biogeographic or environmental barriers. Rather, population structure may reflect refugial lineages that have since expanded their ranges, often leading to secondary contact between once isolated lineages.
(© 2022 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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