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Code and data for "Geographic isolation enables recurrent pollinator shifts despite hybridisation in the Cape's hyperdiverse heathers"

journal contribution
posted on 2024-02-15, 06:35 authored by Seth MuskerSeth Musker, Nicolai NuerkNicolai Nuerk, Michael PirieMichael Pirie

Abstract:

Interrogating the ecological and geographic factors that influence population divergence dynamics can reveal why some groups of organisms diversify more prolifically than others. One such group is the heathers (Erica, Ericaceae), the largest plant genus in the Cape Floristic Region. We study Erica abietina, a highly variable species complex with four subspecies differing in geographic range, habitat, and pollination syndrome. We test for population differentiation, hybridisation, introgression, and pollinator-driven divergence using genotyping-by-sequencing on samples across the entire distribution. We find five variably distinct genetic groups, with one subspecies comprising two independent lineages that are geographically isolated and occur on different soil types. Phylogenetic analysis suggests two independent shifts between bird- and insect-pollination, with accompanying genetic divergence. However, for one pair of populations with different pollinators we uncover several individuals of hybrid origin at a site of sympatry. These results suggest that floral differentiation driven by divergent selection acts in concert with geographic isolation to maintain reproductive isolation and promote speciation. Our investigations reveal a highly dynamic system whose diversity has been shaped by a variety of interacting forces. We suggest that such a system could be a model for much of the diversification of the Cape flora.

The data includes various VCF files needed to reproduce the analyses described in the paper. Code is provided also.

Funding

Deutsche Forschungsgemeinschaft (PI 1169/1-2)

History

Department/Unit

Department of Biological Sciences