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Abstract
North America is a secondary center of diversification of the genus Pinus. Most of these speciation events are fairly recent, producing a pattern of widespread shared polymorphism and fuzzy species boundaries. Among five-needle pines, the relationships among Pinus flexilis, Pinus strobiformis, and Pinus ayacahuite have been particularly difficult to determine. To understand the speciation process and the phylogenetic relationships in this species complex, we evaluated genetic and ecological differentiation using multilocus sequence data and ecological niche model comparisons. Our results show Late Pliocene-Early Pleistocene divergence and a contrasting pattern of differentiation between genes and ecological niche. Cytoplasmic and housekeeping nuclear genes show a clear differentiation of P. ayacahuite. However, ecological niche differences and candidate genes for drought tolerance show a strong differentiation in P. flexilis. Significant correlation was found between genetic distance and environmental distance in some of these candidate genes, as well as evidence of natural selection in P. flexilis.
Parent Publication
Citation
Moreno-Letelier, A.; Ortiz-Medrano, A.; Pinero, D.; Barraclough, T. G. 2018. Genetic and ecological divergence in Pinus flexilis-Pinus strobiformis-Pinus ayacahuite species complex: Clues to understanding speciation in pines. In: Schoettle, Anna W.; Sniezko, Richard A.; Kliejunas, John T., eds. Proceedings of the IUFRO joint conference: Genetics of five-needle pines, rusts of forest trees, and Strobusphere; 2014 June 15-20; Fort Collins, CO. Proc. RMRS-P-76. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 8.
