RACE FOR THE HUMAN GENOME
The Human Genome Project is a federally funded program that set out to sequence the entire 3 billion base-pair human genome. The project started in 1990 and was to be completed in 15 years. At the start of the project, sequencing technology was in its infancy. Chain termination sequencing was becoming refined, but sequencing more than 1000 base pairs of DNA a day was challenging. Within 10 years, the rate of sequencing was substantially greater, and the cost per base had decreased from $10 in 1990 to about 50 cents per base sequenced in the late 1990s. In 1998, Celera Genomics, led by Craig Venter, decided to sequence the entire human genome faster and cheaper. Celera Genomics proved its point by sequencing the entire 180-Mb genome of the fruit fly, Drosophila, between May and December of 1999. Celera used the shotgun sequencing approach, which most researchers thought would not work for such large numbers of data. Celera Genomics then continued with the shotgun approach. The official Human Genome Project was only 85% complete when Celera announced that it had sequenced 99% of the human genome. In June 2000, a joint announcement from Celera Genomics and the Human Genome Project presented the first working draft of the entire sequence of the human genome.
The Human Genome Project started with a good game plan for sequencing the genome. The project first mapped large fragments of human DNA (such as YACs and BACs) to their respective chromosomal locations. Then the fragments of DNA were sequenced. As described earlier, mapping is time consuming but necessary to order the sequence data. At the time of startup, computers were unable to order more sequence data than found in large chromosomal fragments. During the 1990s, computing power increased so rapidly that Craig Venter decided the mapping steps were unnecessary. He sequenced many small fragments of DNA and entered the data into the computer. The computer assembled the information into a working draft. Venter was able to beat his competition largely because of the increase in computer power.