• Question: How do you ensure the samples of DNA are not distorted in transit to and from the other companies? What do you do if the DNA you have read does not make sense?

    Asked by to Ben on 18 Jun 2014. This question was also asked by .
    • Photo: Ben White

      Ben White answered on 18 Jun 2014:

      Hi @mollyainger, good question and one I wish the postman would appreciate more!
      The most important thing when transporting DNA or RNA, is to keep it cool so that it doesn’t start degrading.

      One of the most common ways of transporting DNA is to put it on ice blocks, the kind you put in lunch boxes to keep food chilled/frozen.
      For RNA though, this need to be kept as close to -80 °C as possible, as will degrade very quickly if it gets hot (anything above freezing), and naturally doesn’t stay around in our bodies for long. Scientists therefore normally send this kind of material on dry ice.
      Dry ice has many other uses also- it’s used in movies to make ground fog (think graveyards in horrow films), and also can be used in a number of different experiments… and making videos of exploding coke bottles for youtube: http://youtu.be/G-Ywwy__pxo?t=28s

      When we receive DNA we run lots of different experiments on it to make sure it’s going to be readable, and if it isn’t going to be readable we work with the scientists or companies to get better DNA. Most of the time if we sequence the DNA and it doesn’t make sense it’s because it’s either: something new and exciting that no one has seen before, something that has gone wrong when the scientists were extracting the DNA, or something that needs more data for us to make sense of it. Being able to sequence and read DNA the way we do is at the forefront of science and sometimes takes several scientists working together to make sense of it.

Comments

  • Photo: Rebecca

    Rebecca commented on :

    I agree @mollyainger this is so important! A huge part of my job is to check that we have sequenced exactly what we thought we were sequencing!
    We have a few common problems, like you said, sometimes DNA is not transported correctly, and samples get mixed together or leak out so we ask for them to be sent in exactly the same way by everyone so that the risk of this happening is reduced. But also because the sequencing we use is a fairly new technology and we are collecting from all over the world some people aren’t as familiar with how to make the best DNA. We send out very details instructions to everyone so that it is as easy as possible for everyone to do it exactly the right way!
    Thats how we try to prevent problems happening by having standard guidelines, but some samples do get through and we have to make sure the genomes we use for analysis are top quality!
    I check a number of things like is the genome the right size? (It may seem much bigger if there is also something else mixed in). Is my genome in too many pieces? (my bacteria usually form 50-500 pieces, if there are more than 1000 then I don’t use that data). Does my genome match to most of my example genome? (If its less than 80% the same then it is probably something else and I don’t use the data).
    For any DNA that has been sent that doesn’t look good enough to me I ask for the bacteria to be grown and the DNA collected again and again until I am certain that it is right!