In our last article, we discussed clinical-grade 30x whole genome sequencing (WGS). In this article, we are going to dive deeper into the topic and discuss what different terms such as 30x and 0.4x mean in-relation to genome sequencing.
Let’s first take a step back and discuss what whole genome sequencing is and why it’s valuable.
About Whole Genome Sequencing (WGS)
WGS is a laboratory technique in which the entire coding (exon) and non-coding (intron) regions of the genome are analyzed. It provides a comprehensive map of a person’s entire genetic makeup, which consists of nearly 6 billion letters. That's 6 billion data points for each person's genome!
Whole Genome Sequencing vs Genotyping DNA Tests
WGS is different from traditional consumer DNA tests known as 'genotyping' tests that provide data on part of a person's genome. Genotyping tests, also know as DNA chips and DNA microarrays, are very affordable (usually less than $100 per test) while also being very accurate, which is why they are excellent alternatives to more expensive whole genome sequencing.
Genotyping is the type of DNA testing used most often, especially when DNA tests are sold online. For example, genotyping is the technology we use for our Ultimate DNA Test and it's also the same technology used by 23andMe and AncestryDNA.
Genotyping genetic tests can obtain data on up to 2 million data points. Genotyping tests provide a tremendous amount of useful data for almost everything you'll want to know about your genes (ancestry, health, medication reactions, wellness, nutrition, fitness, sleep, etc). This type of testing may also be used to create an extensive personalized health plan.
So why do some people want whole genome sequencing instead of genotyping? WGS may be preferred if the goal is evaluation of rare diseases, such as Cystic Fibrosis and Tay Saches, or if a person simply wants to obtain as much data as possible.
The Value of Whole Genome Sequencing
WGS is our most powerful tool for testing for genetic disorders such as mutations that cause rare diseases as well as some forms of cancer. It's now also being used for tracking infectious disease outbreaks. WGS has come down significantly in price and, because of this, can now be useful on an everyday basis.
By understanding our genome in its entirety, we are in a better position to outsmart our genes.
What is 30x Whole Genome Sequencing?
When sequencing your genome, there is an important concept known as coverage.
The concept of coverage is similar to megapixels in your camera. The more megapixels your camera has, the clearer the image. The same applies to genome sequencing. The higher the coverage, the better the data quality.
Coverage refers to the number of times the sequencing machine will sequence your genome. Because you have 6 billion letters in your genome, even if the sequencing machine was incredibly accurate 99.99% of the time, the 0.01% error rate means that your genome may have 600,000 errors!
To significantly reduce the potential for errors, most sequencing services will sequence your genome many times! Each additional time further reduces the error rate, which means that the more times your genome is sequenced (ie the higher the coverage), the more accurate the data will be.
When you see genome sequencing being sold, 'x' marks the spot to look for! The number before the 'x' is the coverage (the average number of times your genome will be sequenced).
For example, when you get 30x WGS, the '30x' means that your entire genome will be sequenced an average of 30 times.
Clinical-Grade Whole Genome Sequencing
When sequencing is 30x, this means it is clinical-grade. The term 'clinical-grade' indicates that the genome data is very reliable and, because of this, can be used for health-related purposes.
For example, your doctor may use the data from clinical-grade WGS to determine what diseases you are genetically predisposed to as well as which medications are best for you to take.
If you want your genome sequencing to be clinical-grade, make sure it's 30x.
What is 0.4x Whole Genome Sequencing?
As many people are purchasing 0.4x WGS from companies such as Nebula Genomics, we've started to receive a lot of questions about it. Sequencing.com's bioinformatics team has also spent a lot of time working with actual data from 0.4x sequencing and what they've discovered is amazing.
Let's first understand what 0.4x means. If genome sequencing is only 0.4x, this means that the entire genome is sequenced less than a single time. This means that theoretically, genome sequencing data from 0.4x WGS may contain a lot of gaps in the data.
Benefits of 0.4x WGS
Our bioinformatics team was initially reluctant to work with data obtained from 0.4x genome sequencing because it is a fairly new concept and they were unsure of the data quality. To their surprise, the genome sequencing provided by Nebula Genomics' 0.4x WGS was excellent!
Upon further evaluation, we determined this is because Nebula Genomics applies highly advanced algorithms to the data known as imputation. This serves two purposes. First, it fills in a lot of the gaps and, second, it greatly increases the quality of the data.
While the data is generated by a genome sequencing machine is less with 0.4x WGS compared to 30x, applying imputation substantially increases both the quantity and quality of the 0.4x data. This extra data processing step makes all the difference.
During the first step, hardware (genome sequencing machines in a laboratory) performs the actual testing and generates the initial genome data. During the second step, software (computer algorithms) process and greatly enhance the quantity and quality of the genome data. This is a powerful combination that allows accurate genome sequencing to be performed at an affordable price.
Our bioinformatics team has determined that the enhanced data obtained from 0.4x WGS is so good that it can be used to obtain both ancestry and health information. Similar to genotyping tests and 30x WGS, the enhanced data from 0.4x WGS may also be used to create personalized health plans.
30x versus 0.4x Sequencing
Both 30x and 0.4x sequencing can be used to generate data that can be used for many purposes.
30x is generally preferred when a person is sick. For example, 30x is appropriate when a person with a serious yet unknown illness, such as a baby, may have a rare disease.
0.4x is generally preferred when a person is healthy. For example, 0.4x is appropriate for people who are interested in having their genome sequenced and using the data to improve their health and wellness as well as for ancestry and self-discovery.
|WGS Coverage||Price (USD)||Types of Information Obtained||Often Used By|
|0.4x||~$150||Health, Wellness, Ancestry, Data Exploration||Healthy Person|
|30x||~$500+||Health, Rare Diseases, Wellness, Ancestry, Data Exploration||Sick Person|
The wide assortment of DNA Analysis Apps at Sequencing.com can analyze any genome sequencing data, including both 0.4x and 30x.
Using Sequencing.com’s DNA App Store
In our DNA app store, there are nine categories of apps including health, ancestry, nutrition, fitness, beauty, lifestyle, children, bioinformatics, and clothing. While all of the apps within the store are a great fit, apps like Wellness & Longevity and Genetic Counseling apps are an excellent starting place.
If you already have taken a DNA test or have had your genome sequenced, import or upload your data to obtain insights and personalized guidance not available anyplace else.
If you haven't yet taken a DNA test, you can compare DNA tests here.