The Genetic Ghost Dance: How Epigenetics Governed the Human-Neanderthal Legacy
When Homo sapiens migrated out of Africa and encountered Neanderthals in the Eurasian landscape, the resulting interbreeding was not merely a mixing of two different genomes. It was a collision of two distinct biological histories, each fine-tuned by hundreds of thousands of years of adaptation to vastly different environments. While the physical evidence of this hybridization is written in the 1% to 4% of Neanderthal DNA found in modern non-African populations, the true complexity of this merger lies in the software of the cell: the epigenome. Epigenetics, the study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence, acted as the primary regulatory gatekeeper, determining which Neanderthal traits would persist and which would be silenced in the modern human lineage. The most prominent mechanism in this regulatory battle was DNA methylation. This process involves the addition of a methyl group to specific locations on the DNA molecule...