Genome sequencing – Whole-genome sequencing (WGS)
Genomics is a branch of genetics that studies the DNA in its entirety: the genome of living organisms. The name derives from the term “genome”, meaning an organism’s entire set of DNA instructions and genetic information. It is a relatively new field in biology.
Genome research began in the early 1980s, in parallel to accelerated developments in DNA sequencing technologies, the genetic mapping project and the discovery of the entire genome.
Genomics focuses on statistic and functional analysis of the genetic coding in the cells. To do so, It implements bioinformatic technologies and advanced computer software that can predict the role of genes before conducting scientific experiments.
Genetic screen testing and genome sequencing: what is the difference?
Genomics focuses on changes in the DNA that can indicate diseases or predict them.
There are many genetic testing technologies that are widely known today, they help find out the possibility of being a carrier of a gene related to specific diseases, usually cancer.
Genetic testing can identify genetic mutations that help choose the suitable treatment.
Genomic sequencing identifies many different types of genes and mutations in a single test, based on next-generation genome sequencing that allows screening a large number of genes and mutations simultaneously using a small sample of the tumor.
What do the test results indicate?
The results of genomic sequencing are a genomic profile that provides precise information on the tumor sample. This helps doctors choose the most suitable treatment. Genomic sequence testing diagnoses the tumor tissue and detects genome instability or mutational burden that may cause immunotherapeutic reactions to treatment.
This innovative technology enables a view of person’s entire genetic material simultaneously. This process is divided into segments, the computer then attaches all the segments to one sequence. Each segment is screened dozens of times to calculate which genes deviate from the normal sequence.
The duration of the sequencing process is between one day to a week due to technical abilities. Interpreting the results takes between two to three months. Today, genome sequencing is used mainly in the research of diseases such as cancer, cardiovascular diseases, diabetes and autoimmune diseases.
How much does it cost?
The cost for testing a person’s entire genetic material is around 3,000 USD. It is estimated that this price will decrease substantially in the coming years.
Genome sequencing has pros and cons:
Genome sequencing advantages: All the information in one test
One of genomic sequencing’s biggest advantages is the ability to analyze a person’s entire genetic material in a single test run. It is estimated that test prices will drop to several hundred dollars.
Test results can assist medical treatment in many aspects such as choosing medication and personalizing treatment methods, so they match a patient’s individual needs.
Disadvantages and limitations of genome sequencing
Today, genome sequencing is performed for research purposes only. In the future it should also expand to clinical use. Test costs are considered expensive but are expected to drop in the future.
More disadvantages include:
It is not always possible to determine the cause of the disease – tests results include many genetic aberrations that need to be interpreted to find the cause of the disease. Many of these changes are polymorphic, meaning they have no clinical significance.
Risk for incorrect diagnosis – mutations indicated in genomic sequencing can provide information on the cause of diseases, however, this is not a definite diagnosis since some of the mutations are harmful and may lead to incorrect diagnosis.
Unexplainable findings – many changes remain unexplained or undefined, which may complicate interpretation and make it difficult to find the cause of the disease.
Test failure – technical errors in the interpretation process may occur, that can cause mutations to be mistakenly omitted and not interpreted.
Genome sequencing is considered highly reliable when the disease is defined and there are other patients the results can be compared to. Test reliability when it includes samples from both the child and parents.