Historical biogeography and phylogeny of Cucurbita insights from ancestral area reconstruction and niche evolution

Knowledge of the role of geographical and ecological events associated to the divergence process of wild progenitors is important to understand the process of domestication. We analysed the temporal, spatial and ecological patterns of the diversification of Cucurbita, an American genus of worldwide economic importance. We conducted a phylogenetic analysis based on six chloroplast regions (5907 bp) to estimate diversification rates and dates of divergence between taxa. This is the first phylogenetic study to include C. radicans, a wild species that is endemic to the Trans Mexican Volcanic Belt. We performed analysis of ancestral area reconstruction and paleoreconstructions of species distribution models to understand shifts in wild species ranges. We used principal component analysis (PCA) and multivariate analysis of variance (MANOVA) to evaluate the environmental differentiation among taxa within each clade. The phylogenetic analyses showed good support for at least six independent domestication events in Cucurbita. The genus Cucurbita showed a time of divergence of 11.24 Ma (6.88-17 Ma 95% HDP), and the dates of divergence between taxa within each group ranged from 0.35 to 6.58 Ma, being the divergence between C. lundelliana and C. okeechobeensis subsp. martinezii the most recent. The diversification rate of the genus was constant through time. The diversification of most wild taxa occurred during the Pleistocene, and its date of divergence is concordant with the dates of divergence reported for specialized bees of the genera Xenoglossa and Peponapis, suggesting a process of coevolution between Cucurbita and their main pollinators that should be further investigated. Tests of environmental differentiation together with ancestral area reconstruction and species distribution models past projections suggest that divergence was promoted by the onset of geographic barriers and secondary range contraction and by expansion related to glacial-interglacial cycles.

Bibliographic Details

Main Authors:	Castellanos Morales, Gabriela Doctora autora 14360, Paredes Torres, Leslie M. autora, Gámez Tamariz, Niza Doctora autora 15104, Hernández Rosales, Helena S. Doctora autora 15106, Sánchez de la Vega, Guillermo autor 22551, Barrera Redondo, Josué autor, Aguirre Planter, Erika Doctora autora 22549, Vázquez Lobo Yurén, Alejandra Doctora autora 15105, Montes Hernández, Salvador Maestro autor 22552, Lira Saade, Rafael Doctor autor 15109, Eguiarte Fruns, Luis Enrique Doctor autor 15108
Format:	Texto biblioteca
Language:	eng
Subjects:	Calabazas, Filogenética, Nicho (Ecología),
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