Abstract Detail

Phylogenomics

Karbstein, Kevin [1], Tomasello, Salvatore [2], Hodac, Ladislav [3], Wagner, Natascha [2], Marincek, Pia [2], Barke, Birthe Hilkka [2], Pätzold, Claudia [4], Hörandl, Elvira [2].

Untying Gordian knots: Unraveling reticulate polyploid plant evolution by RRS genomic data using a large non-model species complex.

Speciation via hybridization and polyploidization is a major evolutionary force in plant evolution. However, this is still poorly understood for non-model, neopolyploid groups. Challenges are due to high heterozygosity, low genetic divergence, and missing information on sexual progenitors species, ploidy levels, and reproduction modes. The large Eurasian Ranunculus auricomus species complex possesses diploid to hexaploid, sexual to apomictic populations, and more than 830 described morphospecies. The evolutionarily young complex is thus well-suited to study the addressed issues. A comprehensive workflow integrating reduced-representation sequencing (RRS) genomic data was applied to unravel reticulate evolution, genome diversity and composition of polyploids. Analyses are based on 97,312 RAD-Seq loci, 576 targeted nuclear genes (48 phased), and 71 plastid regions derived from 78 polyploid apomictic taxa and four di- and one tetraploid putative sexual progenitor species. In this talk, I will present the workflow and the applied (phylo)genomic structure, network, and SNP-origin analyses. Results consistently showed only 3–5 supported and geographically structured polyploid genetic groups. Each group contained an extant sexual progenitor species, and surprisingly, one group possessed a yet unknown progenitor. Combined genetic analyses demonstrated predominantly allopolyploid origins, each involving 2–3 different diploid sexual progenitors. Young allotetraploids showed subgenome dominance and non-hybrid SNPs, suggesting substantial post-origin but little lineage-specific evolution. The biodiversity of neopolyploid complexes can result from multiple hybrid origins involving different progenitors and considerable post-origin evolution (e.g., homoeologous exchange, hybrid segregation, or gene flow). The applied workflow demonstrates that RRS genomic data including multi-approach information is efficient to delimit shallow reticulate relationships.

Related Links:
BioRxiv preprint
Homepage Kevin Karbstein

1 - University of Göttingen, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Untere Karspüle 2, Göttingen, Lower Saxony, 37073, Germany
2 - University of Göttingen, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Untere Karspüle 2, Göttingen, 37073, Germany
3 - Max Planck Institute for Biogeochemistry, Department of Biogeochemical Integration, Jena, Germany
4 - Senckenberg Research Institute, Department of Botany and Molecular Evolution, Frankfurt am Main, Germany

Keywords:
allopolyploidy
apomixis
genome composition
Hyb-Seq
nuclear genes
plastome data
RAD-Seq
Ranunculus auricomus.

Presentation Type: Oral Paper
Number: PHYLO I004
Abstract ID:55
Candidate for Awards:None