Phylogenomics and morphometric-environmental modeling unraveled reticulate polyploid evolution of the Ranunculus auricomus complex
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Proposed Symposium Title: Phylogenomics and morphometric-environmental modeling unraveled reticulate polyploid evolution of the Ranunculus auricomus complex
Karbstein, Kevin1,2,3*, Tomasello, Salvatore1, Hodač, Ladislav2, Wagner, Natascha1, Marinček, Pia1, Barke, Birthe Hilkka1, Paetzold, Claudia1,4, Wäldchen, Jana2 & Hörandl, Elvira1
Affiliations: 1 University of Göttingen, Albrecht-von-Haller Institute for Plant Sciences, Göttingen, Germany 2 Max Planck Institute for Biogeochemistry, Jena, Germany 3 Technical University of Ilmenau, Institute for Computer and Systems Engineering, Ilmenau, Germany 4 Senkenberg Naturhistorische Sammlungen, Dresden, Germany * corresponding author: firstname.lastname@example.org
Plant speciation is often occupied by hybridization, polyploidization, or apomixis. However, consequences of partly overlapping, intricate evolutionary processes are still poorly understood for non-model, neopolyploid plant groups. Analytical challenges are attributable to high heterozygosity, low genetic divergence, and missing information on progenitors species, ploidy levels, and reproduction modes. To tackle this, we selected the large Eurasian Ranunculus auricomus species complex, comprising five newly circumscribed sexual species and >800 polyploid taxa/morphospecies. Subgenomic (97,312 RAD-Seq loci, 576 nuclear genes, and 71 plastid regions), flow cytometric leaf/seed (1,474/1,075 screened individuals), geometric morphometric (1587-1880 landmarked individuals/trait), and abiotic environmental datasets were collected from 75 polyploid apomictic taxa and four putative sexual progenitor species. In this talk, an innovative taxonomic workflow will be presented, which includes phylogenomic tree, structure, network, and SNP-origin analyses, and genomic-morphometric-environmental multivariate modeling. Results consistently showed polyphyly and only 3–5 supported groups instead of 80 polyploid morphospecies. Each group contained an extant sexual progenitor species, and surprisingly, one group possessed a yet unknown (probably extinct) progenitor. Combined multi-genomic analyses demonstrated predominantly allopolyploid origins, each involving 2–3 different diploid sexual progenitors, potentially during interglacial periods. Young allotetraploids showed subgenome dominance and non-hybrid SNPs, suggesting substantial post-origin (e.g., hybrid segregation) and little lineage-specific evolution. Sexual progenitors occupied a much smaller range in southern and central Europe, whereas three-times more heterozygous polyploid and predominantly obligate apomictic derivatives expanded their range towards northern and northeastern Europe characterized by more temperature variable habitats. Allopolyploid apomicts, compared to their diploid sexual progenitors, resemble a mosaic of new, more stress-tolerant genotypes with intermediate to transgressive morphotypes often outside the progenitor’s ecological niches, explaining the observed geographic parthenogenesis scenario. The joint evaluation of phylogenomic, cytological, morphological, and ecological data supports a revision of the purely descriptive, subjective traditional morphological classification.