The Human genome project or HGP began in 1990 and was completed in 2003, and was coordinated by the US Department of Energy and the US National Institute of Health. The project was headed by James D. Watson. It was set to determine the complete sequence of base pairs of DNA inside the human genome, because the sequence of DNA bases determines our genetic information. A human genome has about 3 x 109 base pairs and the HGP aimed to identify approximately 20,000-25,000 genes in human DNA, and the average gene consists of three thousand bases. 99.9 per cent of all nucleotide bases are exactly the same in all people. It was identified that we differ from each other, in our DNA sequences at about 1.4 million locations with single-base DNA differences, also known as SNPs or single nucleotide polymorphism. Knowledge about variations in the human genome can help us to diagnose, treat or even prevent disorders and ailments that affect human beings.
The repetitive sequences in DNA shed light on the chromosome structure and evolution. DNA sequences that are repeated many times, sometimes a hundred to a thousand times, in the human genome are called repetitive sequences or microsatellites, but have no coding functions. In fact, less than two per cent of genomes code for proteins. With the advent of advanced genetic engineering methods, it was now possible to isolate and clone a piece of DNA to determine its sequence. Since the HGP aimed to store the entire genome information in databases, it required high-speed computational devices for data storage and retrieval. In addition, the HGP required improved tools for data analysis. Thus, the HGP is credited with contributing to the rapid development of bioinformatics, which involves the application of statistics and computer sciences to the field of molecular biology. Apart from understanding the genetic make-up of the human species, HGP also aimed at non-human species to offer solutions in various sectors such as health, agriculture and energy production.