• Question: 1. How do the DNA sequencing machines work? 2.What does TGAC do with the sequencing of genes in DNA of living organisms one the sequence has been determined?

    Asked by to Dave, Ditte on 18 Jun 2014. This question was also asked by , , , .
    • Photo: Dave Baker

      Dave Baker answered on 18 Jun 2014:

      Wow. Well, one machine uses a ‘flowcell’. It’s like 8 rectangle tubes. On the inner surface of the tubes are little bits of DNA but only one strand and we know the bases in this DNA. So, we get the peices of DNA that we want to sequence or read and make these into one strand (DNA is usually 2). Then we stick these to the DNA on the flowcell. Now we know where it is! We then add 1 unit of DNA, there are 4, a c g t. When this happens a laser blasts this new base or unit of DNA and it flashes out some light. We read this light with a camera, hence read that base. The machine does this hundreds of times and it’s called sequencing by synthesis. Google Illumina!

      Once we have the DNA sequence this is then looked at. Lots of genes have the same structure. Actually ATG is usually the start of all genes, well the first proper building block. There are many reasons to sequence, sometimes just to look at 1 base change that causes a massive change in what the gene does. It’s all good stuff…

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