High-altitude environments present formidable challenges for survival and reproduction, with organisms facing limited oxygen availability and scarce nutrient resources. The yak (Bos grunniens), indigenous to the Tibetan Plateau, has notably adapted to these extreme conditions. This study delves into the genomic basis of the yak’s adaptation, focusing on the positive selection acting on genes involved in nutrient assimilation pathways. Employing techniques in comparative genomics and molecular evolutionary analyses, we selected genes in the yak that show signs of positive selection associated with nutrient metabolism, absorption, and transport. Our findings reveal specific genetic adaptations related to nutrient metabolism in harsh climatic conditions. Notably, genes involved in energy metabolism, oxygen transport, and thermoregulation exhibited signs of positive selection, suggesting their crucial role in the yak’s successful colonization of high-altitude regions. The study also sheds light on the yak's immune system adaptations, emphasizing genes involved in response to various stresses prevalent at elevated altitudes. Insights into the yak’s genomic makeup provide valuable information for understanding the broader implications of high-altitude adaptations in mammalian evolution. They may contribute to efforts in enhancing livestock resilience to environmental challenges.

The escalating challenge of securing sustainable, climate-resilient feed resources necessitates the exploration of novel alternatives. This review critically evaluates the potential of Azolla, a small aquatic fern, as a functional and climate-smart feed ingredient for livestock and poultry. Owing to its symbiotic association with the nitrogen-fixing cyanobacterium Anabaena azollae, Azolla achieves rapid biomass accumulation without external nitrogen input, thereby offering a uniquely low-carbon low-cost cultivation system. Nutritionally, Azolla contains 15-35 % crude protein (dry matter), and serve as a valuable source of essential amino acids, vitamins, minerals, and diverse bioactive compounds that may contribute to improved animal health and product quality. Evidence from feeding trials in poultry and other livestock species consistently demonstrate that Azolla supplementation significantly enhance growth performance, feed efficiency, egg and milk production, immune functions, and overall product attributes, while simultaneously lowering feed cost. Notably, its bioactive profile supports gut integrity, antioxidant capacity, and methane mitigation, emphasizing its dual potential to improve productivity and reduce the environmental footprint of animal agriculture. Azolla's adaptability across agro-climatic zones and capacity for year-round cultivation further reinforce its suitability as a climate-smart feed resource. Despite these advantages, constraints related to large-scale production, preservation, nutrient variability, and the presence of anti-nutritional factors highlight the need for standardized cultivation protocols and innovative processing technologies. This review consolidates current evidence on the nutritional, functional, and ecological value of Azolla and identifies key research priorities to support its broader adoption as a sustainable feed resource for livestock and poultry.

The evolutionary dynamics of immune-related genes GBP5, GZMB, IFNG, IRF7, KLRD1, RTP4, TNFSF4, and TRAT1 were investigated through comprehensive phylogenetic and selection analyses across mammalian species. Using concatenated gene sequences, we applied advanced methods including PAML (a software tool that analyzes evolutionary selection pressures by comparing rates of genetic changes), MEME (a method to identify patterns in protein sequences that may indicate functional sites), and structural modeling (a technique to predict 3D protein shapes) to assess co-evolution and adaptation. Site- and branch-specific selection tests revealed widespread positive selection (ω > 1), with 15–26 branches showing statistically significant adaptive evolution (p < 0.05), particularly in functional domains critical for pathogen recognition and immune regulation. Recombination analysis identified gene-specific patterns, with GBP5, GZMB, and IRF7 exhibiting significant recombination breakpoints, while IFNG and TNFSF4 remained conserved. Functional annotation highlighted the biological relevance of selected sites, linking them to inflammasome activation (GBP5), apoptotic pathways (GZMB), interferon signaling (IFNG, IRF7), and lymphocyte regulation (KLRD1, TNFSF4). Tissue-specific expression analysis confirmed these genes’ roles in immune-active tissues, with enriched pathways including Th1/Th2 differentiation (KEGG hsa04658) and cytokine regulation. These findings underscore the persistent evolutionary arms race between hosts and pathogens, with immune genes adapting to maintain effective defense mechanisms. The study provides a framework for understanding mammalian immune gene evolution, offering insights into conserved functional domains that may inform therapeutic targeting and vaccine design. By integrating phylogenetics, selection analysis, and functional genomics, we elucidate the molecular signatures of adaptation in key immune regulators, advancing our knowledge of host-pathogen coevolution.