Human DNA sequencing

Modern technology advancement resulted in a development of unique methods for DNA diagnostics. One of those methods is genome sequencing – method that uncovers the nucleotide sequence of DNA.  Ten years ago Human genome project was completed at the cost of 2.7 billion dollars. It required scientists from 20 international institutions to work for over 13 years. Now days, there are some private pilot projects that can complete human DNA sequencing in a few month with the cost of one to five thousand dollars.

Exome Sequencing

Over the years, scientists figured out that in order to obtain useful information about clinical applications of DNA sequencing they need only fraction of DNA. The actual protein-coding part of the genome constitutes only 1% of total DNA. That coding DNA is called exome. There are about 20 000 genes in human exome. Mutations in exome genes cause 85% of all genetical problems. This means that by sequencing exome only we can 5685get almost the same information at the small fraction of the cost.  Presently exome can be sequenced for as little as 500$ by some companies.

How exome DNA sequencing works?

First, person who wants to know his or her DNA sequence should provide a biological sample (spit or swab from the inside cheek is enough).

Then scientists will extract DNA from the sample, and break it into the short fragments. Analyse them using DNA microarray or automated sequencing equipment or some other techniques, depending on the clinical needs.

Exome sequencing options

Some people may want to examine only part of the exome regions that are known to encode genes that can cause significant health problems. There is about 57 genes mutation in which can cause 24 different genetical diseases. Mutations in nearly half of those genes may increase the risk of cancers. Some genes are linked to the heart problems and others to the adverse reaction to anesthetics. Such sequencing will be chipper and faster.

Who should consider exome sequencing?

•    Individuals who are likely to have a genetical condition but the diagnose is unclear

•    Individuals who have a genetic condition that could be caused by several genes.

•    Individuals with an undiagnosed disorder who want to know if genes cause it.

What is the meaning of the gene sequencing results?

Not all mutations can cause a disease. But also, the absence of mutation cannot guarantee you that you won't get sick. Clinical laboratories usually provide clients with a report and explain the risks of mutations that are found.