Polyploidy Facilitated Survival and Alpine Adaptation of Species-rich Subtribe Tussilagininae (Asteraceae: Senecioneae) during Middle Miocene Global Cooling and Andean uplift

Yet, well-documented cases with robust evidence remain rare. We here investigate subtribe Tussilagininae (Asteraceae: Senecioneae), a species-rich group with a complex origin involving three successive allopolyploid events.

Using genome-scale homeolog phasing and extensive fossil calibrations, we show that two allopolyploidy events giving rise to Tussilagininae s.s. occurred at ~14–13.4 Ma, followed by a third event forming the Andean Gynoxyoid group at ~5.3 Ma. Significantly, these estimates are robust to random fossil calibration subsampling and coincide closely with the major climate cooling during Middle Miocene and rapid Andean uplift, respectively, suggesting that polyploidy facilitated Tussilagininae’s survival and adaptation during severe temperature declines.