Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 19, one copy inherited from each parent, form one of the pairs. Chromosome 19 spans about 64 million base pairs (the building blocks of DNA) and represents more than 2 percent of the total DNA in cells.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 19 likely contains between 1,300 and 1,700 genes.

Genes on chromosome 19 are among the estimated 20,000 to 25,000 total genes in the human genome.