What is a genome?

Your genome is the complete set of DNA contained in virtually every one of your cells. Your genome is like a blueprint — containing all of the instructions needed to make and maintain the function of every cell, tissue and organ in your body.

pairs of chromosomes
~ 3 billion
base pairs
> 99%
identical across all humans

A genome is the entire set of genetic material for an organism. The human genome consists of about 3 billion base pairs of DNA across 23 pairs of chromosomes. More than 99 percent of the human genome is the same in all people. That means that differences in less than 1 percent of our genome accounts for the vast diversity of humans across the globe.


Alberts, B., et al (2008). Molecular biology of the cell. New York, NY: Garland Science; Hartl, D.L. and Jones, E.W. (2005). Genetics: analysis of genes and genomes. Sudbury, MA: Jones and Bartlett Publishers.