New genomic research confirms that human genomes are remarkably similar, with about 99.6% of DNA shared between any two people. The remaining 0.4% difference comes from millions of small genetic variants, including single-letter changes and larger structural differences. Although most of these variants have no biological effect, a small fraction influences physical traits, disease risk, and how individuals respond to medications. These findings highlight how tiny genetic differences can have significant impacts on human diversity and health, shaping the future of personalized and genomic medicine.
