Data from: The long-term evolutionary potential of four yeast species and their hybrids in extreme temperature conditions

Accelerating climate change and extreme temperatures urge us to better
understand the potential of populations to tolerate and adapt to thermal
challenges. Interspecific hybridization can facilitate adaptation to novel
or extreme environments. However, predicting the long-term fitness effects
of hybridization remains a major challenge in evolutionary and
conservation biology. Experimental evolution with microbes provides a
powerful tool for tracking adaptation across generations and in real time.
We investigated the thermal adaptation dynamics of four species of budding
yeast (Saccharomyces) and their interspecific F2 hybrids, for 140
generations under cold (5°C) and warm (31°C) conditions. We found
significant variation in the evolutionary potential of species and
hybrids, strongly determined by their natural temperature tolerance. The
largest fitness improvements occurred in hybrids, with some populations
nearly quadrupling in fitness in the cold environment, exceeding both
parents in thermal adaptive potential. While adaptation rates in some
hybrid populations were high, their absolute fitness by the end of
evolution was comparable to that of their parents. Reciprocal
transplanting of evolved populations from the endpoint of evolution into
opposite temperatures revealed that hybrids had greater resilience when
challenged with sudden temperature shifts. Our results highlight that
hybridization alters the fitness outcomes of long-term adaptation to
extreme environments and may render populations more resilient to sudden
environmental change, presenting both opportunities and challenges for
conservation and sustainable agriculture.