New genomic research confirms that human genomes are remarkably similar: approximately 99.6% of DNA is shared between any two people. The remaining 0.4% comprises millions of genetic variations, including single-letter changes and broader structural differences. While the majority of these variations have no biological effect, a small fraction influences physical characteristics, disease risk, and how individuals respond to medications. These findings demonstrate how even very small genetic differences can have a major impact on human diversity and the future of personalized genomic medicine.
