Exome Sequencing: It?s Easy to Interpret the Life Password
Posted by Andrea Brook on December 25th, 2015
In simple terms, the exome is the genetic code of the protein in the encoding group. The sequencing machine can read only a certain number of bases at a time, but by sequencing the exome, the researchers can generate more bases fast. Compared with the whole genome sequencing, it can also make better resolution with lower cost.
Hybrid strategy
The sequencing of the exome is simply a special form of target enrichment, which is a strategy to prepare the genetic fragments of interest before decoding the sequence. Researchers take advantage of the money and maximize efficiency: if you don't need the whole genome, why do you want to test it? At the same time, after reducing the base of each sample, the researchers can measure more samples at a higher degree of coverage.
Coverage degree refers to the number of times a given base is read by a sequencing machine. But the figures are given, not absolute. 30 times of overage degree means that the average base reads 30 times. Some base reads more frequently, and the other is the opposite. This is enough for many applications. However, it is best to cover a given nucleotide as much as possible when required to read a rare variant of a critical mutation in a heterogeneous cancer and in clinical decision making.
Some researchers use target enrichment to select a small amount or a few hundred genes for sequencing. In exome sequencing, the target sequence is the entire exon of the human genome. Typically, this is a sequence of about 30 MB base. Users will add 5 'and 3' non translation region, small molecule RNA, long non encoding transcripts and other selected specific regions, which will significantly expand the number of captured raw materials. Nextera, for example, has two types of rapid acquisition of Illumina kit. The kit has types: one is the capture of 214,405 exons (37 MB) of the basic kit, and the other is to join the non translation region and small molecule RNA (62 MB) of the extended version of the kit.
