Abstract:

The phenomenal advances in sequencing techniques and analytical development during the last decade have provided a unique opportunity to unravel the evolutionary history of lineages under complex patterns of evolution. This is the case of the largest clade of the ginseng family (Araliaceae), the Asian Palmate group (AsPG), where the large internal polytomies and genome incongruences detected in previous studies pointed to a scenario of radiation with hybridization events between genera for the early evolution of the group. In this study, we aim to obtain well-resolved nuclear and plastid phylogenies of the AsPG using Hyb-Seq to evaluate the radiation hypothesis and assess the role of hybridization in the early evolution of the group. We performed concatenated- and coalescent-based phylogenetic analyses from the 936 targeted nuclear loci and 261 plastid loci obtained for 72 species representing 20 genera of the AsPG and the main clades of Araliaceae. The impact of hybridization and incomplete lineage sorting (ILS) was assessed with SNaQ, and genome duplications were evaluated with ChromEvol. Our nuclear and plastid phylogenies are compatible with a scenario of early radiation in the AsPG. Also, the identification of extensive signals of hybridization and ILS behind the genome incongruences supports hybridization as a major driving force during the early radiation. We hypothesize a whole-genome duplication event at the origin of the AsPG, followed by a radiation that led to extensive ILS, which, alongside the early inter-genera hybridization, is obscuring the phylogenetic signal in the early evolution of this major clade.

Key words: Araliaceae, hybridization, Hyb-Seq, incomplete lineage sorting, radiation, whole‐genome duplication