Table 1.
Recent studies in chicken genomics have identified various genes in specific genomic regions that have crucial roles in heat tolerance.
| Trait Influenced by HS | Candidate Genes | Functions | Chicken Strain | References |
|---|---|---|---|---|
| Body temperature | USP22, KCNH6, MYL4, MIF, ACE, DDX42 | Disruption of DNA synthesis, RNA processing and translation, cell signaling, apoptosis, and blood vessel development | Broiler × Fayoumi AIL | [50] |
| Body temperature | EZH2, RAD21, GSK3B, MLH1, RTEL1 | Apoptosis, cellular stress responses, DNA repair, and metabolic oxidative stress | Broiler-type indigenous chicken | [52] |
| Body weight | HHEX, MARCH5, HECTD2, IDE, TNKS2, KIF11 | Apoptosis, immune response, and DNA synthesis | Broiler × Fayoumi AIL | [50] |
| Digestibility | SLC13A5, PITPNM3, XAF1, TXNDC17 | Protein synthesis, membrane permeability, and free radical damage | Broiler × Fayoumi AIL | [50] |
| Heat tolerance | TSHR | Photoperiodic response in chickens | Indigenous chickens in tropical regions | [53] |
| Heat tolerance and immune response | HSP70, HSPA9, HSPH1, HSP90AB1, PLCB4 | Heat shock response and immune system activation | Iranian indigenous chickens | [20] |
| Lack of feathers | FGF20 | Development of spur and feathers in chicken | Scaleless chickens | [54] |
| Mortality under heat stress | LRP11, HTR2B, EIF2B5, SOD2, DBH, ERN1 | Linked to various immune and physiological functions | White Leghorn layer line | [51] |
| Production, physiological, and egg quality traits | SSTR2, SOX9, HRAS, IRF7 | Cellular stress response and immune response activation | Commercial white egg-laying hens | [55] |
| Response to heat stress | CEP78, MEF2C, VPS13A, ARRDC3 | Heat stress resistance in birds | F2 chicken population | [56] |
| Stress response | THADA, TRPC3, MOV10L1, RAD51B, TGFB2 | Cellular stress response, DNA repair, apoptosis, and metabolic oxidative stress | Indigenous broiler chickens | [57] |
| Survival to acute heat stress | VGFR4, SLC16A2, COX7B, AGPAT5, HSF2BP, SLC35F2 | Genes are linked to ubiquitin-mediated proteolysis, metabolism, and homeostasis. | Commercial layer chickens | [6] |
| Thermotolerance | SCEL, KCNS2, STK3 | Heat stress resistance | Broiler-type strain Taiwan country chickens | [52] |
| Viral titer under heat stress | CAMK1d, CCDC3 | These genes are responsible for immune response in chicken. | Hy-Line Brown layer chickens | [49] |
| Viral titer under heat stress | TIRAP, ETS1, KIRREL3, ST3GAL4 | Adaptive immune response | Hy-Line Brown layer chickens | [49] |
USP22: Ubiquitin-Specific Peptidase 22, KCNH6: Potassium Voltage-Gated Channel Subfamily H Member 6, MYL4: Myosin Light Chain 4, MIF: Macrophage Migration Inhibitory Factor, ACE: Angiotensin-Converting Enzyme, DDX42: DEAD-Box Helicase 42, EZH2: Enhancer of Zeste Homolog 2, RAD21: RAD21 Cohesin Complex Component, GSK3B: Glycogen Synthase Kinase 3 Beta, MLH1: MutL Homolog 1, RTEL1: Regulator of Telomere Elongation Helicase 1, HHEX: Hematopoietically Expressed Homeobox, MARCH5: Membrane-Associated Ring-CH-Type Finger 5, HECTD2: HECT Domain E3 Ubiquitin Protein Ligase 2, IDE: Insulin-Degrading Enzyme, TNKS2: Tankyrase 2, KIF11: Kinesin Family Member 11, SLC13A5: Solute Carrier Family 13 Member 5, PITPNM3: Phosphatidylinositol Transfer Protein Membrane-Associated 3, XAF1: XIAP-Associated Factor 1, TXNDC17: Thioredoxin Domain Containing 17, TSHR: Thyroid-Stimulating Hormone Receptor, HSP70: Heat Shock Protein 70, HSPA9: Heat Shock Protein Family A (Hsp70) Member 9, HSPH1: Heat Shock Protein Family H (Hsp110) Member 1, HSP90AB1: Heat Shock Protein 90 Alpha Family Class B Member 1, PLCB4: Phospholipase C Beta 4, FGF20: Fibroblast Growth Factor 20, LRP11: LDL Receptor-Related Protein 11, HTR2B: 5-Hydroxytryptamine Receptor 2B, EIF2B5: Eukaryotic Translation Initiation Factor 2B Subunit 5, SOD2: Superoxide Dismutase 2, DBH: Dopamine Beta-Hydroxylase, ERN1: Endoplasmic Reticulum To Nucleus Signaling 1, SSTR2: Somatostatin Receptor 2, SOX9: SRY-Box Transcription Factor 9, HRAS: HRas Proto-Oncogene, GTPase, IRF7: Interferon Regulatory Factor 7, CEP78: Centrosomal Protein 78, MEF2C: Myocyte Enhancer Factor 2C, VPS13A: Vacuolar Protein Sorting 13 Homolog A, ARRDC3: Arrestin Domain Containing 3, THADA: THADA Armadillo Repeat Containing, TRPC3: Transient Receptor Potential Cation Channel Subfamily C Member 3, MOV10L1: Mov10-Like RISC Complex RNA Helicase 1, RAD51B: RAD51 Paralog B, TGFB2: Transforming Growth Factor Beta 2, VGFR4: Vascular Endothelial Growth Factor Receptor 4, SLC16A2: Solute Carrier Family 16 Member 2, COX7B: Cytochrome C Oxidase Subunit 7B, AGPAT5: 1-Acylglycerol-3-Phosphate O-Acyltransferase 5, HSF2BP: Heat Shock Transcription Factor 2 Binding Protein, SLC35F2: Solute Carrier Family 35 Member F2, SCEL: Sciellin, KCNS2: Potassium Voltage-Gated Channel Modifier Subfamily S Member 2, STK3: Serine/Threonine Kinase 3, CAMK1d: Calcium/Calmodulin-Dependent Protein Kinase ID, CCDC3: Coiled-Coil Domain Containing 3, TIRAP: Toll-Interleukin 1 Receptor (TIR) Domain Containing Adaptor Protein, ETS1: ETS Proto-Oncogene 1, Transcription Factor, KIRREL3: Kin of IRRE-Like 3 (Drosophila), ST3GAL4: ST3 Beta-Galactoside Alpha-2,3-Sialyltransferase 4.