One of the great achievements of modern science has been the sequencing of the human genome, which was largely completed by 2003.

Recombinant DNA is a DNA in which nucleotide sequences from different sources - often different species - are combined in vitro into the same DNA molecule. The methods for making recombinant DNA are central to genetic engineering (the direct manipulation of genes for practical purposes).

Scientists can make recombinant DNA and then introduce it into cultured cells that replicate the DNA and express its genes, yielding a desired protein. For example, Golden rice, a genetically modified crop to which has been added a battery of genes that overcome deficiencies in vitamin A and iron, was planted for the first time in Asian fields.

Neurobiologists for the first time caught a glimpse of the molecular basis of learning. DNA technology has launched a revolution in the area of biotechnology, the manipulation of organisms or their components to make useful products.