The
exome is the part of the
genome formed by
exons, the sequences which when transcribed remain within the mature
RNA after
introns are removed by
RNA splicing. It consists of all DNA that is transcribed into mature RNA in cells of any type as distinct from the
transcriptome, which is the RNA that has been transcribed only in a specific cell population. The exome of the
human genome consists of roughly 180,000
exons constituting about 1% of the total
genome, or about 30 megabases of
DNA. Though comprising a very small fraction of the
genome,
mutations in the exome are thought to harbor 85% of
mutations that have a large effect on disease.
Exome sequencing has proved to be an efficient strategy to determine the genetic basis of more than two dozen
Mendelian or
single gene disorders.