Experimental evolution in a warming world - the omics era.

A comprehensive understanding of the genetic mechanisms that shape species responses to thermal variation is essential for more accurate predictions of the impacts of climate change on biodiversity. Experimental evolution with high-throughput resequencing approaches (E&R) is a highly effective tool that has been increasingly employed to elucidate the genetic basis of adaptation. The number of thermal E&R studies is rising, yet there is a dearth of efforts to integrate this new wealth of knowledge. Here we review this literature showing how these studies have contributed to increase our understanding on the genetic basis of thermal adaptation. We identify two major trends: highly polygenic basis of thermal adaptation and general lack of consistency in candidate targets of selection between studies. These findings indicate that the adaptive responses to specific environments are rather independent. A review of the literature reveals several gaps in the existing research. Firstly, there is a paucity of studies done with organisms of diverse taxa. Secondly, there is a need to apply more dynamic and ecologically relevant thermal environments. Thirdly, there is a lack of studies that integrate genomic changes with changes in life-history and behavioural traits. Addressing these issues would allow a more in-depth understanding of the relationship between genotype and phenotype. We highlight key methodological aspects that can address some of the limitations and omissions identified. These include the need for greater standardisation of methodologies and the utilisation of new technologies focusing on the integration of genomic and phenotypic variation in the context of thermal adaptation.