Genetics Find consumer-friendly information about the effects of genetic variation on human health. 👁 Genetic Conditions Genetic Conditions Learn about the signs and symptoms, causes, and inheritance of more than 1,300 health conditions with a genetic basis. 👁 Genes Genes Find information about the function of more than 1,400 genes and see how changes in these genes are related to health conditions. 👁 Chromosomes and mtDNA Chromosomes and mtDNA Read about each of the 23 pairs of human chromosomes and mitochondrial DNA (mtDNA). 👁 Help Me Understand Genetics Help Me Understand Genetics Explore topics in human genetics, from the basics of DNA to genomic research and personalized medicine.