Abstract:

Contemporary developmental biology recognizes that the genome is not a static or deterministic code but functions as an adaptive device capable of dynamically responding to environmental demands through gene expression regulation. This responsive capacity is the foundation of phenotypic plasticity, essential for the survival and adaptation of offspring to the external world. Epigenetics, defined as the study of modifications that alter gene expression without changing the DNA sequence, is the primary molecular mechanism governing this flexibility. Epigenetic modifications, including DNA methylation, histone modifications, and non-coding RNAs (ncRNAs), are crucial for proper brain development, synaptic function, and neural circuit formation in the central nervous system. Epigenetics thus translates environmental eventual experiences into permanent or semi-permanent genetic instructions, enabling the organism to generate a biological response (such as that mediated by the neuroendocrine stress axis Hypothalamic-Pituitary-Adrenal, HPA) that aligns with the emotional state and surrounding environmental context. The central thesis of this discussion is that this tuning between biology and emotion is entirely mediated by the epigenetic configuration established during critical developmental periods, primarily gestation.