Animal Molecular Breeding, 2025, Vol.15, No.1, 1-8 http://animalscipublisher.com/index.php/amb 2 genes, especially EPAS1, where a new missense mutation (Q579L) is overrepresented in high-altitude populations. This mutation is responsible for improved oxygen transportation and utilization, most likely resulting in increased red blood cell counts and hemoglobin content, which are of crucial importance in successful oxygen delivery under hypoxia (Song et al., 2016; Wang et al., 2016a). 2.2 Regulatory mechanisms of the cardiovascular and metabolic systems Genomic analyses show that metabolic regulation genes and cardiovascular development genes are under strong selection in plateau goats. Introgressed gene PAPSS2 of wild markhor is strongly correlated with adaptability at high altitude and includes hypoxia-related pathways. Other candidate genes, such as CDK2, SOCS2, NOXA1, and ENPEP, are implicated in adaptation to hypoxia, suggesting that cardiovascular and metabolic pathways are tightly regulated to maximize blood supply, vascular development, and metabolic efficiency during hypoxic stress(Song et al., 2016; Wang et al., 2016b; Li et al., 2022). 2.3 Immune system responses to plateau environments Adaptation to the harsh plateau environment also encompasses enhanced immune system function. Candidate genes such as CNGA4, Camk2b, and several interleukins (IL7, IL5, IL23A) have been implicated in enhanced immune response and protection from exogenous stressors. These genetic adaptations likely enhance resistance to pathogens and environmental stress, conferring overall health and viability in high-altitude regions. Additional immunity-associated genes and pathways, including the serpin cluster, INFGR1, and TLR2, have also been identified as targets of selection in plateau-adapted goat populations (Chen et al., 2020; Tian et al., 2021; Ghanatsaman et al., 2023). 2.4 Adaptive regulation in reproductive and developmental processes Reproductive and developmental flexibility in plateau goats is regulated by complex networks of mRNAs, miRNAs, and lncRNAs that mediate ovarian function and reproductive efficiency. These key pathways involve ovarian steroidogenesis, meiosis in oocytes, and amino acid biosynthesis, which are all linked to fertility and adaptive capacity. Such molecular networks regulate the development of germ cells and oocytes and interact with immune and metabolic processes to ensure reproductive success and plasticity in unfavorable environments (Lv et al., 2024). Such adaptations are vital for population viability and productivity under plateau conditions. 3 Research Progress on Plateau Adaptation-Related Genes in Goats 3.1 Identification and screening of candidate adaptive genes Exome sequencing and whole-genome sequencing are being used, along with high-density SNP chips, in recent research to identify candidate genes for high-altitude adaptation in goats. EPAS1, PAPSS2, LEPR, LDB1, EGFR, FGF2, ENPEP, SIRT6, and CDC42 are a few such genes that play a role in hypoxia response, cardiovascular development, and energy metabolism (Wang et al., 2016a; Song et al., 2016; Jin et al., 2020; Li et al., 2022). In addition, DSG3 was discovered to be a candidate hypoxia adaptation gene through targeted resequencing, which determined specific SNPs that distinguish highland and lowland populations (Kumar et al., 2018). Immune genes CNGA4 and Camk2b were also discovered to contribute to environmental defense and adaptation (Tian et al., 2021). 3.2 Findings from genome-wide association studies (GWAS) and selective sweep analyses GWAS and selective sweep analysis identified genomic regions under strong selection within arms length plateau goats. For example, a region spanning PAPSS2, introgressed from markhor, exhibits strong association with adaptation to high altitudes (Li et al., 2022). Selective sweep analysis also demonstrated that genes such as CDK2, SOCS2, NOXA1, and ENPEP are selected for hypoxia adaptation (Wang et al., 2016b). VEGF pathway and its genes (e.g., FGF2, EGFR, AKT1, PTEN, KDR) are highly enriched in high-altitude humans, validating their roles in vascular and metabolic adaptation (Jin et al., 2020). The findings provide a genetic basis for phenotypic disparity between highland and lowland breeds of goats.
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