How many genes does a human being have?

The human genome is the complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. Human genomes include both protein-coding DNA genes and noncoding DNA.

Before the completion of the human genome project, many scientists were expecting to find 100,000 or more genes in our genome. This was based on the assumption that because we are one of the most complex creatures on Earth we should have lots of genes. However, it turned out we only have around 24,000 genes.