GENOME SEQUENCING

Full genome sequencing (FGS), also known as whole genome sequencing, complete genome sequencing, or entire genome sequencing, is a laboratory process that determines the complete DNA sequence of an organism's genome at a single time. This entails sequencing all of an organism's chromosomal DNA as well as DNA contained in the mitochondria and for plants the chloroplast as well. Almost any biological sample—even a very small amount of DNA or ancient DNA—can provide the genetic material necessary for full genome sequencing. Such samples may include saliva, epithelial cells, bone marrow, hair (as long as the hair contains a hair follicle), seeds, plant leaves, or anything else that has DNA-containing cells. Because the sequence data that is produced can be quite large (for example, there are approximately six billion base pairs in each human diploid genome), genomic data is stored electronically and requires a large amount of computing power and storage capacity. Full genome sequencing would have been nearly impossible before the advent of the microprocessor, computers, and the Information Age.

Full genome sequencing should thus not be confused with DNA profiling. The latter only determines the likelihood that genetic material came from a particular individual or group and does not contain additional information on genetic relationships, origin or suspectability on specific diseases. It is also distinct from SNP genotyping which covers less than 0.1% of the genome. Almost all truly complete genomes are of microbes; the term "full genome" is thus sometimes used loosely to mean "greater than 95%". The remainder of this article focuses on nearly complete human genomes.

In general, knowing the complete DNA sequence of an individual's genome does not, on its own, provide useful clinical information, but this may change over time as a large number of scientific studies continue to be published detailing clear associations between specific genetic variants and disease.

The first nearly complete human genomes sequenced were J. Craig Venter's (caucasian at 7.5-fold average coverage) and James Watson's (caucasian male at 7.4-fold)., a Han Chinese (YH at 36-fold) a Yoruban from Nigeria (at 30-fold) female leukemia patient (at 33 and 14-fold coverage for tumor and normal tissues), and Seong-Jin Kim (Korean at 29-fold) . Other full genomes have been sequenced but not published, and as of June 2009, commercialization of full genome sequencing is in an early stage and growing rapidly.