The term Genome Sequencing is familiar to those who have studied Biological Sciences, and perhaps those who are capable of giving their full attention to the breakfast news. For those who aren’t so familiar, it is only a matter of time before you will have easy access to what makes you ‘you’.
The genome is essentially the unique code for our genetic make-up. Adenine (A), Cytosine (C), Guanine (G) and Thymine (T) bases are ordered in such a way that a shorter sequence, known as a gene, can be expressed as a protein. Sequencing the genome gives us access to the sequences that are coding and also non-coding, and its introduction into modern society has been such an important breakthrough for determining how us humans have come to be.
It is no easy task working out our sequence, as the human genome consists of approximately three billion bases. If you don’t think this is that big, consider that it is estimated that it would take you about 31 years to count to one billion! The Human Genome Project, which aimed to confidently establish the first ever human genome sequence, began in 1990. It was only in 2003 that the project was complete, and the cost of this achievement came in at nearly $3 billion. After all that time and money, was it really worth sequencing another genome?
Well, let’s just say that what I love the most about science is its ability to keep on moving – progress is made every day. Sequencing technology has drastically improved, allowing the coding of an average Joe’s genome to be feasible. When Google-ing the current cost of whole genome sequencing, I came across the company Dante Labs which was advertising a home kit. A saliva sample could be collected and sent off, and after a 10 to 12-week wait, results with a 99.7% accuracy were returned. All this for just €399.
As its accessibility increases, it becomes more likely that the number of people with knowledge of their genome sequence will also increase. Knowing exactly what it is that makes us different to everyone else is an exciting prospect and if it’s easy enough to find out, then why not? What potential does genome sequencing offer in today’s society, and for possible future endeavours?
Understanding Disease Risk
Many people with rare disorders are misdiagnosed, or have no diagnosis at all. The 100,000 Genomes Project, which I have previously written about, aims to sequence the genomes of 70,000 people* to understand the genetics of rare disorders and cancers. The genome of a patient is compared to that of a healthy family member and differences are looked at in greater detail. It may be that a unique mutation results in the expression of a faulty protein, which contributes to the symptoms associated with the disorder. This leads onto the second point…
The ability to pinpoint the genes responsible for genetic diseases could lead to the introduction of personalised medicine. The NHS plans to introduce this as an alternative to the ‘one size treats all’ approach of healthcare. Let’s use breast cancer as an example of personalised medicine that is currently applied. Breast cancer can be caused by a mutation in the HER2 gene, which encodes a growth receptor. The patient is HER2-positive if a mutation is present, and HER2-negative if a mutation is absent. Whereas HER2+ patients can be treated with the Herceptin, HER2- is non-responsive to the drug. Initially testing the patient to see whether they express HER2 can determine which treatment is better. Applying this to the sequenced genome, other treatments can be determined based on whether a patient with a particular mutation would benefit from the action of a drug, in turn allowing the patient to be treated more quickly and saving the health service valuable resources.
One born (and sequenced) every minute
It is plausible that in the future, every birth could be coupled with the complete knowledge of their genetic make-up. Parents could be advised early on that their child has a risk of a deficiency, and modify the child’s upbringing to accommodate for it before any severe symptoms show. For example, a lack of the amino acid phenylalanine that is associated with Phenylketonuria (PKU) could be resolved with a diet of high-protein foods before eczema or even neurological problems developed. The benefit of this would be that a lot preventable cases could be reduced. Would paying for the sequencing and identification of possible health complications of each child reduce the average cost of treatment per person in the long-run?
What could our genome tell others?
If our genome was sequenced, who would have the right to access it? Could our sequence be accessed by pharmaceutical companies, wanting to sell us a personalised product? Could it be used against us, providing insurance companies with evidence that you were at a higher risk of developing health-related problems or were more prone to stress? Furthermore, would we even know who had seen our genome and what had been done to it; is it possible for someone to ‘steal’ your genome sequence if it’s free property? On the other hand, if we were to restrict which findings we are notified of, this brings up an ethical issue. Imagine that a professional notices a mutation associated with an increased risk of cancer. The customer, however, has specified that they only want to know about certain characteristics, such as whether they are more at risk of gaining weight. If that professional warns that individual, then they are at risk of breaching confidentiality.
Mainstream genome sequencing will require stricter regulations to ensure that it is introduced into our society responsibly. Keep your eye out for updates on the news – and possibly on the Dante Labs website in case there are any further reductions.
*The number of participants is lower than the number of genomes because the genome of a cancerous cell (from a tumour) differs from that of the healthy cells of that patient. Comparing the genome of a healthy cell to that of a tumour cell allows identification of the mutations that have contributed to the onset of cancer.