Significance of epigenetics for understanding brain development, brain evolution and behaviour

Area of Science:

• Evolutionary biology
• Neuroscience
• Genetics

Background:

• Mammalian evolution features two key environmental shifts impacting brain development: viviparity and placental development.
• Viviparity necessitated hypothalamic modifications for maternal care, parturition, and feeding, influenced by placental hormones.
• Epigenetic marks, specifically imprinting, evolved for regulating parent-of-origin gene expression, crucial for hypothalamus and placenta function.

Purpose of the Study:

• To explore the impact of viviparity and placental development on mammalian brain evolution.
• To investigate the role of epigenetic regulation, particularly imprinting, in brain development.
• To understand the evolutionary significance of the matriline in shaping maternal capabilities and neocortical development.

Main Methods:

• Comparative analysis of mammalian evolutionary adaptations.
• Examination of genetic and epigenetic regulatory mechanisms in brain development.
• Review of literature on imprinting, hypothalamic function, placental development, and neocortical evolution.

Main Results:

• Viviparity and placental development drove significant hypothalamic adaptations for maternal-offspring interactions.
• Epigenetic imprinting plays a vital role in the co-adapted evolution of the hypothalamus and placenta.
• Primate neocortical evolution has led to behavior less dependent on hormones, with epigenetic processes enabling transgenerational adaptability.

Conclusions:

• The interplay between maternal and fetal genomes under viviparity created selection pressures for enhanced mothering traits.
• Epigenetic mechanisms, particularly those influenced by the matriline, are critical for neocortical development and adaptability.
• Dysregulation of epigenetic processes, especially during critical developmental timing in the neocortex, can contribute to neurological and psychiatric disorders.