All living beings have a secret code written in their bodies. The code is responsible for almost all physical and behavioral features of life. Brown or green eyes, tall or short height, and even our behavior, almost everything is pre-determined by the code. Half of our code comes from our mother and the remaining half from our father. That’s why it’s also responsible for the inheritance of traits from one generation to another. Reading this code can inform us about our health status, genealogy, and any future risks.
Whether you’re interested in getting sequenced yourself or just want to learn more about this exciting new field, keep reading! But first, I’d like to welcome the readers of JCSG.org. I hope you find this information useful.
What is a genome
The code of life is called the genome, and it is written in the form of four letters (ATGC) in different combinations. The human genome is made up of 6.4 billion such letters. These letters control most of who we are and even how we behave. Even a single change in the letter can cause substantial physical and functional problems in the body. For example, a one-letter change in the code that makes red blood cells would make faulty blood cells, i.e., causing sickle cell anemia. Another example is cystic fibrosis disease caused by the removal of only three letters from the genome at a specific location.
What is whole-genome sequencing?
Whole-genome sequencing is a technology that can read the complete genome. This includes the genome of humans, which is made up of 6.4 billion letters.
What is the purpose of whole-genome sequencing?
The purpose of whole-genome sequencing is to detect known genetic diseases and predict the risk of complex genetic diseases such as stroke or cancer. It can also help monitor new genetic diseases that are not known yet.
What is whole genome sequencing used for?
Whole-genome sequencing is widely used for research purposes. Researchers can study viruses and how they cause diseases. They study how the human body develops and performs regular functions in the womb.
What are the benefits of genome sequencing?
Genome sequencing provides a full resolution picture of the code responsible for who we are. Millions of years of evolution and inheritance can be observed in the genome. For example, 5-8% of the human genome is made up of viral genes accumulated through thousands of years of viral infections. Once you know your code, you will learn about any potential issues or known genetic risks. You will also learn about any genetic disorders that may be discovered later.
Imagine that scientists find that at site 20,545, if the letter “T” was changed with “A,” you are more likely to develop heart disease. If you have your genome sequenced, you can check the site and know if an A or T is present at the site.
What is the process for genome sequencing?
As the genome comprises four letters of DNA, the first step is to extract the DNA. Many sequencing technologies are available, but the most basic one is the chain termination method. In this method, fluorescent-labeled modified letters (A, T, G, C) are used that, when added to the genome, produce a color. We can precisely know the DNA sequence or the code by reading this color. For instance, ATGC is read like green, red, black, and blue. The whole human genome can be sequenced in days using automatic machines that can detect color.
What is the difference between genetic testing and genome sequencing?
Genetic testing, or DNA testing, is a service that sequences only a part of your genome and is what’s used for genetic genealogy. This is done to find important letters that play a vital role. Most genetic testing companies decode less than 0.02% of your DNA and assume that the remaining code is the same or unnecessary. For example, if you have ATCCGC as a gene, they sequence T because it is the most common place where a change can happen. However, knowing that T is present in the second place does not mean that your remaining sequence is correct.
Genomic testing provides more accurate results than genetic testing because it will give you a whole 6.4 billion-letter picture. Let us understand the difference with another example:
Imagine that there are two known codes, CLOCK, and BLOCK. Knowing that the first letter is C or B will give you an idea if you have a CLOCK or BLOCK, but it assumes that the remaining letters are the same and ignores the fact that it could also be BULL or CHALK. All combinations of ATGC are possible, even deletions or insertions of letters.
Is Next Generation Sequencing the same as whole genome sequencing?
Next-Generation Sequencing (NGS) is a technique (or a group of techniques to be more accurate). These techniques are used to read or sequence the full genome quickly. For example, it took 13 years for scientists worldwide to sequence the first genome. This was done using traditional sequencing technologies, which cost around 3 billion dollars. Thanks to the NGS, we can now sequence a whole human genome in a matter of days in a small laboratory.
How much does whole genome sequencing cost?
The cost of genome sequencing has decreased drastically in the past two decades. Currently, it costs around 100 dollars to sequence an entire human genome. However, sequencing will only give you the 6.4 billion letters. The more challenging part is making sense of such big data and what the letters represent. For that, we need bioinformaticians who can help us understand what it means to have a particular sequence.
What companies currently offer consumer tests?
Most of the companies offer genome sequencing services only to researchers. Only a few companies provide genomic sequencing to consumers. One company called Nebula Genomics offers such services. As sequencing becomes more affordable and post-sequence analysis becomes more efficient, the number of companies providing consumer genomics is expected to increase.
Does 23andMe do whole genome sequencing?
No, 23andMe uses genetic testing through common variants. The test determines what letters are present at important sites. For example, one person might have the DNA letter A while another person might have a C at a particular site. It only determines a fraction of the full genome, and the rest of the code is assumed to be the same.
Consumer genomics is an accurate and high-resolution approach to traditional genetic testing. However, it is expensive, and the data produced through it (making sense of 6.4 billion letters) is hard to analyze.
With the advances in technologies, it will become more affordable and easier to understand, making it an attractive option for people who want to get their genome sequenced. This shift toward whole-genome sequencing is sure to bring about exciting new discoveries that could improve human health. Are you curious about your own genome?