S4.19 Reading the book of life: A brief history of DNA sequencing
Hello, and welcome to Genetics Unzipped - the Genetics Society podcast, with me, Dr Kat Arney. In this episode we’re taking a look at how we learned to read the book of life, from the earliest days of DNA sequencing to the very latest futuristic technologies.
Ever since we found out that DNA contains the instructions for life, we’ve been trying to decipher its contents.
Most of us will be familiar with the DNA double helix. It’s a twisted ladder, where the struts up the sides are long chains of sugary molecules and the rungs slung in between are made up of pairs of four chemical ‘letters’ called bases, usually known by their initials A (for adenine), G (guanine), C (cytosine) and T (thymine). The order that these letters come in the ladder is known as a DNA sequence, and reading that order is referred to as sequencing.
Just as a child learning to read starts with something easy like Sarah And Duck rather than War and Peace, science’s efforts to sequence DNA started small.
Throughout the late 1970s and early 80s, researchers began by reading the genetic makeup of viruses that attack bacteria, known as phages. The first whole genome to be published – a heroic feat back in 1976 – belonged to an RNA phage called MS2. It was just 3,500 letters long and contained only four genes, but it was a start.
Today, sequencing machines in labs around the world are churning out billions of basepairs of DNA data, and the very latest techniques even promise to allow us to read DNA inside cells. The cost of reading a whole human genome has gone from $2.7 billion dollars for the first one to a few hundred or even less or even zero, depending on how you count it and who’s paying.
And as you’ll know if you’re a fan of this podcast, widespread, cheaper access to rapid DNA sequencing has revolutionised almost every aspect of life sciences research, from personalised medicine and clinical diagnostics to conservation, infectious diseases, evolutionary biology and much, much more.
We’ve come a long way since those early days. So how did we get from there to here?
The birth of DNA sequencing
The earliest days of DNA sequencing in the 1970’s starts with a theoretical physicist called Walter Gilbert, his student Allan Maxam as well as British biochemists Fred Sanger and Alan Coulson. Click here to explore more about the birth of DNA sequencing.
DNA sequencing: the next generation
Scientists knew that if they wanted to take a leap forward in the speed of DNA sequencing, they needed to stop relying on synthesising DNA fragments and then looking at them afterwards, and start analysing the DNA synthesis process in real-time, reading off each letter directly as it was added. Click here to learn more about how this was achieved.
The future of DNA sequencing
Despite the enormous advantages and potential of next-generation sequencing, science, as always, marches onwards. We are still creating new ways to read the book of life and push forward the frontiers of genetics. Click here to discover what is coming next for DNA sequencing.
That’s all for now. We’ll be back next time taking a look at the genetics of music. Is musical ability in your genes? Or can you blame being tone deaf on your DNA too? As a musician as well as a scientist, I’ve been wanting to make this episode for a long time, and I can’t wait to share it with you.
For more information about this podcast including show notes, transcripts, links, references, music credits and everything else head over to geneticsunzipped.com You can find us on Twitter @geneticsunzip and please do take a moment to rate and review us on Apple podcasts - it really makes a difference and helps more people discover the show.
Genetics Unzipped is written and presented by me, Kat Arney with additional research and scripting by Emily Nordvang. It is produced by First Create the Media for The Genetics Society - one of the oldest learned societies in the world dedicated to supporting and promoting the research, teaching and application of genetics. You can find out more and apply to join at genetics.org.uk. Our theme music was composed by Dan Pollard, and the logo was designed by James Mayall, and audio production was by Hannah Varrall. Thanks for listening, and until next time, goodbye.
Music and sound effects licensed from Epidemic Sound
Output from an ABI 373 DNA sequencer, Image courtesy of National Human Genome Research Institute
