Searching for “keys” to animal’s domestication (review)

The dynamics of global environmental changes, the qualitative novelty of emerging new ecosystems (M.R. Kerr et al., 2025), and the reduction of biodiversity, including agricultural species, attract increasing attention to the search for domestication mechanisms. In this regard, the relationships between domestication and its impact on environmental changes in its implementation, as well as the main physiological and molecular genetic systems involved in domestication processes are considered. Accumulated data indicate that the same phenotypic changes in animals in their molecular genetic basis are more often convergent than parallel (J. Yang et al., 2024), involving close metabolic pathways but different genes in variability. A relatively greater contribution to intra- and interspecific differentiation of metabolic pathways associated with adaptation to environmental conditions is noted compared to the action of artificial selection factors (P.A.S. Fonseca et al., 2024). No qualitative differences were found between domesticated and closely related wild animal species in characteristics of protein-coding gene variability, namely, the ratio of non-synonym-ous/synonymous substitutions in amino acid codons (D. Castellano et al., 2025), the difference in number of protein--coding gene copies exceeding those known for genes of supergene families between closely related wild species (X. Feng et al., 2017). All pairwise compared animal species, including those unconventional for studying domestication processes (e.g., songbirds, laboratory mouse lines, rats, and silkworms) show pronounced changes in gene expression profiles in brain structures. Since the formation of regulatory systems of multicellular organisms is based on mobile genetic elements (transposons, TEs) and their recombination products, two main pathways of their involvement in the control of gene expression profiles are considered: 1) preservation of gag genes of exogenous retroviral precursors to form exosomes like a viral capsid for transporting signaling molecules to other cells (W.S. Henriques et al., 2024), 2) participation of TEs in the formation of binding sites for transcription regulation factors, the integration of TEs into genes encoding such factors, and direct TE-induced changes in the epigenetic characteristics of different genomic regions, namely DNA methylation, histone modification, generation of regulatory non-coding RNAs (for example, circular RNA, microRNA and lncRNA) (A. Gebrie et al., 2023). Genomic comparisons of domestic, wild and reintroduced domestic rabbits indicate accelerated disappearance of “domestic” alleles in the latter, mostly associated with nervous activity and with binding sites for certain transcription regulation factors (P. Andrade et al., 2024). It can be expected that the search for such regions of genomic DNA will contribute not only to the clarification of domestication mechanisms, but also to their practical application.