Skip to 0 minutes and 11 seconds In the last 60 years, our ability to study the human genome has changed immeasurably. Before 1956, we did not even the exact number of chromosomes present within human cells. Our ability to look at chromosomes down a microscope in the form of a karyotype dates back to this time and was the main diagnostic technique used in cytogenetics until the 21st century. It was not until the 1970s that a scalable, economical method for reading the sequence of DNA was introduced. Using this technology in combination with the new method to amplify sections of DNA, known as PCR, allowed scientists to map the first human disease gene in the early 1980s, the cause of a devastating neurological condition called Huntington’s Disease.
Skip to 1 minute and 4 seconds The increased knowledge of the sequence of the human genome allowed researchers to develop fluorescent probes which would stick to specific places on human chromosomes. This enabled cytogeneticists to apply the probes to chromosomes and cells from patients, to see if those specific regions of the genome were present, absent, or duplicated– a technique known as Fluorescent In Situ Hybridisation, or FISH. Meanwhile, academics across the world were in a huge race with a private company to be the first to sequence the human genome, trying to keep the genetic sequence free to use for all humanity. This fierce battle was won just in time by the public sector and ensured that all researchers had free access to the human genome for health care purposes.
Skip to 1 minute and 56 seconds The published reference sequence of the human genome meant that probes could be developed across the entire set of 23 chromosomes and allowed scientists to develop a technique called Array CGH, allowing cytogeneticists to interrogate gains and losses of any parts of the genome. We will discuss this technique and the impact it has had on clinical practice in the next few steps. Finally, the drive to sequence the first human genome had pushed scientists into developing ever faster and economical methods of DNA sequencing, resulting in the development of what became known as Next-Generation Sequencing, or NGS technologies.
Skip to 2 minutes and 38 seconds Since the publication of the first genome sequenced using NGS from James Watson, one half of the duo who cracked the structure of DNA back in 1952, the cost and length of time taken to sequence the human genome has fallen exponentially. The number of disease genes identified now stands at over 4,000, with new genes being reported in the medical literature every month. This evolution in genomic technologies over just over half a century is about to transform the practice of health care.
The changing landscape of genomic technologies
This video looks at how various technologies have impacted on medicine over the last 60 years.
During the video, we learnt that, in 1998, a private company run by Craig Venter, initially called the Institute of Genomic Research and later renamed Celera Genomics, announced that they were working to sequence the human genome.
Celera Genomics planned only to make the information from their sequencing available to paying customers with a plan to patent 6000 genes. Celera was in direct competition with the Human Genome Project, an international consortium working to make genomic data freely available online.
As it turned out, both Celera and the Human Genome Project published their draft human genome sequences in 2000.
- Let us know what you think about the race to the human genome. Can you imagine a world where the human genome sequence is privately owned? How would this have shaped medicine today?
- Some people suggest that the competition was a good thing - accelerating discovery. What do you think?
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