Lately, it seems as if we are constantly hearing stories about genome and DNA sequencing. But, these stories often fail to explain exactly what this scientific process is. How are you supposed to know if genome sequencing is right for you if you don’t know what it is? Is there a difference between genome sequencing and DNA testing? Does it hurt to get it done? Is it expensive? How can genome or DNA sequencing benefit you?
These are all perfectly common and normal questions that thousands of people have about this relatively new science. Unfortunately, when people begin looking for answers to these questions, they are often met with complex scientific explanations. When you are looking for answers to a confusing topic and are met with an explanation that is equally confusing, it can be outright frustrating. So, let’s try to simplify things.
The first thing to know is that what we know of the human body today is something that early scientists and medical practitioners couldn’t even fathom. While we have heard of genome sequencing and DNA testing for some time, in reality, it is still a new practice.
Modern medical practices began to emerge in the 1800s. During this time, the average life expectancy of someone living in a city environment was around 25-30 years. For someone living in a more rural environment, life expectancy could reach into the early 40s. Today, the average life expectancy for people living in the United States is about 75-80 years. And though experts predict there will be a temporary decline in life expectancy because of COVID19, many believe that by the year 2050, general life expectancy can reach closer to 100.
There are many factors that contribute to people living longer. One of the biggest reasons is the continued advancements made in the fields of medicine and biology. As scientists gather a greater understanding of how the human body is built and works, they are able to develop means of preserving a higher quality of human life.
In 1869, Swiss physician Friedrich Miescher first discovered Deoxyribonucleic acid (DNA) while examining discarded surgical bandages under a microscope. His discovery spurned a new area of study in medicine, the study of genetics. It wasn’t until 1943 that the collaboration between Canadian-American physicians and geneticists Oswald Avery, Colin MacLeod, and Maclyn McCarty identified DNA as what we recognize it today, the double helix structure responsible for carrying the genetic material of the cells of living organisms.
In the mid-1980s, the US government took notice of several medical experts entertaining the idea of determining the base pairs of human DNA, and then forming a complete map that would sequence human genomes. In 1990, funded by the National Institutes of Health, The Human Genome Project was officially launched.
The $3 billion international project came to a close on April 14, 2003, with the sequencing of 85% of human genomes. There were several flaws in the sequencing, such as multiple gaps and the fact that the map was a composite work of genomes from several human subjects.
In January of 2022, researchers revealed that they had finally closed all the gaps to fully sequence human genomes. So what exactly is genome sequencing, it is the mapping of an organism’s entire DNA makeup.
This is where things can often get confusing for the average person, understanding the difference between genomes and DNA.
A genome is the genetic material of an organism that is coded in said organism’s DNA. DNA is a nucleic acid made up of molecules that deliver genetic instructions. All of human DNA is nearly identical, it is the 0.01% of DNA that is different in individuals that determine specific traits. These traits are attributed to genes and chromosomes.
One way of explaining it is by comparing genomes and DNA to a book. Genomes, in this scenario, represent the whole book. In the book, there are 23 chapters, represented by the chromosomes. The chapter is structured by a collection of paragraphs or genes. Each paragraph is made up of letters or in this case, DNA.
It’s still confusing, which helps explain why it took so long to map the billions of parts that make up genome sequencing. Early forms of genome sequencing relied on manual methods such as Maxam–Gilbert Sequencing developed by Allan Maxam and Walter Gilbert, or Sanger Sequencing, developed by Frederick Sanger. The Human Genome Project spent 13 years working with the Sanger method to partially complete genome sequencing. The process was extremely time-consuming and costly, making it a nonviable method.
The ultimate goal was not to simply sequence genomes for scientific study but to apply the process to patients for life-saving practices. As computer sciences developed, the ability to sequence genomes more rapidly was explored. A paper titled Genome/Exome Sequencing in Clinical Practice, Disease Gene Discovery, and Gene Therapy by Dr. Joseph Jankovic, illustrates the faults of methods such as Sanger Sequencing.
“Although effective and accurate, the high throughput of this method was severely limited by reaction time and length of read, which is less than 1 kilobase, limiting use for single-gene testing or small-gene panels,” Dr. Jankovic says. He explains that a new method, simply called next-generation sequencing, can “rapidly generate large amounts of high-quality DNA sequence information in a relatively inexpensive and efficient manner.”
Dr. Jankovic goes on to say, “The sequence of the human genome was derived using Sanger sequencing over a 13-year period, and subsequent Sanger sequencing of human genomes took roughly a year, but next-generation sequencing can now accomplish the same feat in hours.” Thanks to next-generation sequencing, genomes and DNA can be mapped and read in a manner that is economically and time efficient. This brings up the next question, why should you have your genomes sequenced?
Through genome sequencing, doctors can identify genetic traits vital for prolonged healthy life. Genome sequencing can allow a doctor to recognize how certain medications may interact with a specific patient. Genome sequencing can allow a fertility doctor to select the most viable egg for IVF procedures. Genome sequencing can provide doctors with enough information to pinpoint certain genetic faults parents may pass on to children. Genome sequencing can identify traits in a patient that could be indicative of certain diseases.
There is so much that genome sequencing can reveal about individual patients that it begs the question, who wouldn’t want their genomes sequenced?
Unfortunately, when genome sequencing practices first came about, they were still very expensive. In August of 2009, Stephen Quake, founder of Helicos Biosciences, announced that he had sequenced his own genome with the company’s Single Molecule Sequencer. The sequencing, according to Mr. Quake, cost a little less than $50,000 to complete.
In 2011, Illumina lowered the price of its Personal Full Genome Sequencing Service from $48,000 to $5,000 per human genome, or $4,000 if ordering 50 or more genomes to be sequenced. Considering that there are between 50,000 and 100,000 genomes in the human body, to fully sequence a person’s genomes was still not an option for the average person.
By the late 2010s, the cost of the procedure had decreased to roughly $1,000 per genome sequenced. But as technology has advanced, private companies like Illumina, Helicos Biosciences, IBM, GE Global, and many more have been pushing to bring that price down even lower. Some even claim that in the future, it could cost as little as $100 for genome sequencing.
Today companies like Ancestry.com, 23AndMe.com, and CRIGenetics.com offer rapid inexpensive DNA tests. On average, these DNA kits cost between $60-$200. Finding coupons to lower the cost is also relatively easy. For these tests, you harmlessly collect a saliva sample per the kit’s instructions. Then you send it back to the company and await your DNA results. Results can be ready anywhere from a few days to a few weeks.
These DNA tests are not complete genomic profiles. They just scratch the surface of what an individual’s genomes contain. From a basic DNA test, ancestry and basic genetic markers can be found. For a more in depth study, a lengthier sequencing process is needed.
For full genomic sequencing, larger samples such as blood may be required. The results will take noticeably longer, and the cost will be much greater. But, the information gathered from fully sequencing your genomes can change the course of your life.
When Friedrich Miescher first identified DNA in discarded bandages, the world of medical science began to change. From that moment on, a drive to fully understand what the human body is comprised of has been the root of countless medical studies.
By being able to map genomes, detailed knowledge of what makes each human on this planet different can be made a reality. These differences could be as trivial as knowing what color hair your unborn child will be born with to discovering the likelihood of cancers before they can be even detected in the body. This knowledge could be the key to extending the human lifespan well into the hundreds. Genome sequencing can allow patients to live long healthy lives.