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bioRxiv · 10.1101/2022.01.05.475097

A western representative of an eastern clade: phylogeographic history of the gypsophilous plant Nepeta hispanica

Ramos-Gutierrez, I.·Moreno Saiz, J. C.·Fernandez-Mazuecos, M.
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Abstract

The preference of certain plant species for gypsum soils leads to disjunct population structures that are thought to generate island-like dynamics potentially influencing biogeographic patterns at multiple evolutionary scales. Here, we study the evolutionary and biogeographic history of Nepeta hispanica, a western Mediterranean plant associated with gypsum soils and displaying a patchy distribution with populations very distant from each other. Three approaches were used: (a) interspecific phylogenetic analyses based on nuclear DNA sequences of the ITS region to unveil the relationships and times of divergence between N. hispanica and its closest relatives; ((b)phylogeographic analyses using plastid DNA regions trnS-trnG and psbJ-petA to evaluate the degree of genetic isolation between populations of N. hispanica, their relationships and their genetic diversity; and (c) ecological niche modelling to evaluate historical distributional changes. Results reveal that N. hispanica belongs to an eastern Mediterranean and Asian clade diversified in arid environments since the Miocene-Pliocene. This species represents the only extant lineage of this clade that colonized the western Mediterranean, probably through the northern Mediterranean coast (southern Europe). Present Iberian populations display a high plastid genetic diversity and, even if geographically distant from each other, they are highly connected according to the distribution of plastid haplotypes and lineages. This can be explained by a scenario involving a complex history of back-and-forth colonisation events, facilitated by a relative stability of suitable conditions for the species across the Iberian Peninsula throughout the Quaternary.

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Ramos-Gutierrez, I., Moreno Saiz, J. C., Fernandez-Mazuecos, M.. 2022-01-06. A western representative of an eastern clade: phylogeographic history of the gypsophilous plant Nepeta hispanica. https://doi.org/10.1101/2022.01.05.475097

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