Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 23 2 2021 03 01 A Genome-Wide Association Study of Survival to Unexpected Acute Heat Stress in a F2 Chicken Population بررسی ارتباط چند شکلی ماندگاری ناشی از تنش گرمایی در یک جمعیت F2 مرغ 283 292 16531 EN H. Asadollahi Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran. R. Vaez Torshizi Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran. A. Ehsani Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran. A. Masoudi Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran. Journal Article Heat stress, or hyperthermia, can have a serious effect on chicken performance in poultry industry in many parts of the world. Both genetics and environment play key role in the performance of a chicken and, therefore, it is important to consider both factors in addressing heat stress. On genetics level, genome-wide association studies have become a popular method for studying heat stress in recent years. A population of 202 F₂ chickens was reared for 84 days to find genes and genomic regions affecting growth traits and immune system. But, due to unexpected acute increase in temperature at day 83, 182 birds died (case) and 20 birds remained alive (control). At the age of 70 days, blood sample of all birds was collected to extract their DNA, using modified salting out method. All samples were genotyped by a 60 K Single Nucleotide Polymorphism (SNP) chip. Genome-wide association study was carried out by GCTA to identify gene and genomic regions associated with heat stress tolerance. Results indicated a close relationship between 28 SNPs, located on chromosomes 2, 3, 5, 6, 7, 12, 19, 20, and 21 and heat stress tolerance at the level of suggestive significance. Two suggestively significant markers on chromosome 5, namely, GGaluGA273356 and Gga_rs16479429, were located within and 52 Kb downstream of two genes, including <em>MAPKBP1</em>and <em>SPON1</em>, respectively. Gene ontology analysis indicated that the resistance of chickens to acute increase of temperature might be linked to the function of <em>MAPKBP1</em> and <em>SPON1</em> genes and their biological pathways. These results will be useful for understanding the molecular mechanisms of SNPs and candidate genes for heat stress tolerance in chickens and provide a basis for increasing genetic resistance in breeding programs. https://jast.modares.ac.ir/article_16531_aac8f7d518e4300ab8031d6709164f1d.pdf