The Human Genome Project - The Puffer Fish And Mouse Genomesare Sequenced

In July 2002 the DOE Joint Genome Institute (JGI), operated by the University of California at Lawrence, the University of California at Berkeley, Lawrence Livermore National Laboratory in California, and Los Alamos National Laboratory in New Mexico, announced the draft sequencing, assembly, and analysis of the genome of the Japanese puffer fish (Fugu rubripes). The Fugu Genome Project was initiated in 1989 in Cambridge, England, and in November 2000 the International Fugu Genome Consortium was formed, headed by the JGI. During 2001 the puffer fish genome was sequenced and assembled using the whole genome method pioneered by Celera. Puffer fish was the first vertebrate genome to be publicly sequenced and assembled in this manner and the first vertebrate genome published after the human genome. According to the JGI, puffer fish have the smallest known genomes among vertebrates (animals with bony backbones or cartilaginous spinal columns—fish, reptiles, birds, and mammals, including humans). The puffer fish sequence has about the same number of genes as the considerably larger human genome, but is more compact because it contains relatively little of the junk DNA present in the human genome sequence.

Comparison of the human and puffer fish genomes enabled investigators to predict the existence of nearly 1,000 previously unidentified human genes. Although the function of these additional genes is as yet unknown, they contribute to the complete catalog of human genes. Ascertaining the existence and location of genes helped scientists begin to describe how they are regulated and function in the human body. Of the more than 30,000 puffer fish genes identified, the vast majority of human genes have counterparts in the puffer fish, with the most significant differences in genes of the immune system, metabolic regulation, and other physiological systems that are not alike in fish and mammals.

On December 5, 2002, the first draft of the sequence of the mouse genome was published in Nature. The mouse genome findings were deemed among the most important in terms of their comparability with humans. Mice and humans have about the same number of genes—approximately 20,000—and DNA base pairs—mice have 2.5 billion and humans have 2.9 billion. More important, about 90% of genes associated with medical disorders in humans have counterparts in mice. This finding means that mice are especially well suited for studying diseases that afflict humans and for testing therapeutic treatments for disease.