Meat consumption has been increasing with the enrichment of the global pupation. The rising frequency of heat stress puts the livestock industry at risk, as animals are affected by the rise of temperatures. Pigs are particularly affected, causing both discomfort to the animal and an economical loss to the farmers. Tropical pig breeds such as the Creole pigs are well adapted to high temperatures. A crossbreeding Creole pigs and Large White cosmopolitan pigs (known for their high growth rate) was setup at INRAE to investigate the genetic determinism of heat adaptation in pigs. During my internship, I studied the whole blood transcriptome of the backcrossed offspring of a Creole x Large White cross. We processed a differential expression analysis between the whole blood of genetically related pigs living in tropical environment (French Guadeloupe) and in temperate environment (Charente, France), as well as between different time points along a 2 weeks experimental heat stress of the pigs living in the temperate environment. We identified multiple differences: pigs living in a tropical environment develop acclimatization capacities, with most differentially expressed genes focusing on the response to cellular stress, while pigs living in a temperate environment are capable of expressing a wider range of genes, which can be associated with their optimal living conditions. Moreover, when pigs living in temperate environment experience an acute heat stress event, they are hardly capable of coping with the event within two days, but are capable of expressing particular genes associated with what we may call an immediate acclimatization mechanism. The next analysis step consisted of detecting the genetic variants associated with the expression levels of genes. Multiple quantitative trait locus affecting the expression (eQTLs) were detected, with most being located near the gene they regulate, and a few detected as distant to the gene they regulate. 26% of transcripts were associated with an eQTL, and only 3.4% of total transcripts were associated with two or more eQTLs. Further analysis are needed to detect eQTLs specific to the acute heat stress response, as well as potential genetic × environment interactions on gene expression.