Redband trout ( Oncorhynchus mykiss gairdneri) is a subspecies of rainbow trout inhabiting interior regions of the pacific northwest. Populations of redband trout thrive in different environments ranging from cold montane forests to hot deserts, making them a good model to study adaptation to climate change. When acclimated in common garden, desert populations have demonstrated higher thermal tolerance and better cardiorespiratory performance than those from montane forests . This is suggesting the phenotypic divergence in adaptive traits has a genetic basis. One challenge in studying the genetic architecture of local adaptation is to achieve high marker density to detect candidate genes in natural populations that often have small blocks of linkage disequilibrium. Recently , we used low coverage whole-genome resequencing to identify genome regions associated with both population differentiation and adaptive traits. Results suggest one region on O. mykiss chromosome 4 was consistently the most significant not only among populations, but also in the associated with acute and chronic thermal tolerance, as well as cardiac performance. Thus, the CERK (ceramide kinase) gene from this region appears to be a strong candidate gene in thermal adaptation. In particular, the association with cardiac function suggests a key role of CERK to influence pathways that lead to enhanced oxygen delivery in ectotherms that experience hypoxic conditions in warming environments. With the advancement of whole- genome resequencing and bioinformatics, genomic signatures of adaptation to climate change can be anticipated to be gradually discovered.