Identifying Climatic Drivers of Hybridization with a New Ancestral Niche Reconstruction Method

Area of Science:

• Evolutionary Biology
• Phylogenetics
• Paleoecology

Background:

• Hybridization is common, but the environmental drivers remain unclear.
• Pleistocene range shifts are proposed but lack quantitative validation.

Purpose of the Study:

• To test hybridization hypotheses in Heuchereae using paleoclimatic data.
• To identify environmental factors driving hybridization opportunities.

Main Methods:

• Phylogenetic analysis of 277 nuclear loci and chloroplast genomes for 83 Heuchereae species.
• Coalescent simulations to test hybridization.
• Novel ancestral niche reconstruction method using paleoclimate data from the late Pliocene.

Main Results:

• Confirmed previous and identified one new intergeneric hybridization event in Heuchereae.
• Inferred hybridization events occurred in the mid- to late-Pleistocene.
• Linked hybridization to range contractions into refugia driven by climate change.

Conclusions:

• Past climate change significantly influenced species range dynamics and hybridization.
• Contrasting species' ecological strategies shaped novel range contacts and hybridization.
• The new ancestral niche method is a valuable tool for comparative studies.