Human Accelerated Regions & brain Development: A Summary
Scientists have been studying “Human Accelerated Regions” (HARs) – sections of our DNA that are highly conserved in other mammals but have changed rapidly in teh human lineage since we diverged evolutionarily. Around 3000 of these HARs have been identified, typically averaging 260 base pairs in length.
Interestingly, most HARs don’t code for proteins themselves, but instead act as regulators of gene expression, essentially controlling when, how much, and how strongly other genes are activated during development – like “molecular volume controls.”
Recent research at UC San diego has focused on HAR123, which is present in chimpanzees and mice but has evolved quickly in humans. This study suggests HAR123 plays a crucial role in human brain development by regulating the production of neuronal progenitor cells (NPCs) – the cells that become both neurons and glial cells.
Key Findings:
Neuron-Glia Balance: HAR123 coordinates the ratio between neurons and glial cells. This balance is vital for brain development, synapse function, and neuroplasticity (our ability to learn).
Cognitive flexibility: Researchers believe HAR123 may contribute to cognitive flexibility – the ability to learn and adapt existing knowledge.
* Potential Link to neurological Disorders: Imbalances in neuron-glia ratios are implicated in conditions like autism, schizophrenia, Alzheimer’s, and Parkinson’s, suggesting HAR123 could be involved in these diseases.
Future Research:
Further investigation is needed to fully understand HAR123’s molecular effects and determine if the human version confers unique neuronal properties. This research could ultimately lead to a better understanding of the molecular basis of neurological developmental disorders.