Evolution of DNA methylation in the human brain

Area of Science:

• Neuroscience
• Epigenetics
• Evolutionary Biology

Background:

• DNA methylation is crucial for brain development, function, and disease.
• Understanding epigenetic changes during human brain evolution is key to deciphering human cognition and disease susceptibility.

Purpose of the Study:

• To elucidate DNA methylation alterations during recent human brain evolution.
• To investigate cell-type and context-specific epigenetic changes.
• To link epigenetic evolution to human-specific gene regulation and neuropsychiatric disease risk.

Main Methods:

• Analysis of DNA methylation patterns across different cell types and evolutionary timescales.
• Comparative epigenomic analysis focusing on CG and non-CG (CH) methylation contexts.
• Integration of epigenetic data with genetic risk factors for neuropsychiatric disorders.

Main Results:

• Demonstrated dynamic, cell-type, and context-specific DNA methylation trajectories during human brain evolution.
• Observed increased non-CG (CH) methylation in neuronal gene bodies, leading to human-specific gene down-regulation, particularly in early development.
• Identified reduced CG methylation in cis-regulatory regions, causing gene up-regulation, with a significant portion of neuron-oligodendrocyte differential methylation emerging in the human lineage and linked to schizophrenia risk.

Conclusions:

• Recent epigenetic evolution of the human cortex has significantly shaped the cellular regulatory landscape.
• These epigenetic shifts contribute to human-specific gene expression patterns.
• The study highlights the role of recent epigenetic evolution in increased vulnerability to neuropsychiatric diseases like schizophrenia.