Pig farming faces significant financial losses due to aggressive behavior in individual pigs. Such aggression leads to skin and tail injuries, followed by infections and death. This review summarizes research on genetic and epigenetic mechanisms underlying aggressive behavior in pigs highlighting associations with different SNPs located in intergenic, intronic, and regulatory gene regions. These loci contain a large number of transposable elements (TEs), which occupy 37.9% of the porcine genome and are identified in more than 80% of all protein-coding genes. TEs contribute to cis-, trans-, and epigenetic regulation and serve as important sources for the emergence and evolution of non-coding RNAs. The review discusses the key role of TEs in pig embryogenesis, brain development, and the pathogenesis of neurodegenerative diseases. SNPs associated with aggressive behavior in pigs are likely to affect TE sequences, disrupting their activation and influencing the expression of non-coding RNAs involved in the regulation of brain functions. TEs are highly sensitive genomic sensors for environmental influences, activated by stress, viruses, hormonal fluctuations, and anabolic steroids. TE redistribution and recombination also influence CNV changes associated with aggressive behavior in pigs. TE activation promotes the development of inflammatory processes in the brain, while increased expression of genes involved in immune system function and inflammation has been detected. Differences in the expression of specific genes in the pig and wild boar brain may be due to structural changes in the porcine genome influenced by TEs during breeding, which affects epigenetic features of gene regulation. Increased aggression in certain pig breeds and individual pigs may be related to specific TE redistribution patterns in their genomes. The review suggests strategies for further research on the role of TEs in aggressive behavior and methods to influence them for correcting impaired epigenetic regulation.
Mustafin et al. (Sun,) studied this question.