• Question: What is your favourite experiment?

    Asked by jobibear to Adam, Joanna, Louise S, Louise W, Marcus on 12 Nov 2012. This question was also asked by rosiered, incredablehulk, kbfyt.
    • Photo: Joanna Giles

      Joanna Giles answered on 12 Nov 2012:

      My FAVOURITE experiment is purifying DNA from human blood cells.

      I have to do this quite a lot in my lab so that I can identify what genes people have. These days you can buy neat little kits that can allow you to burst cells (using a special detergent that interacts with the membrane to break apart the bonding of the bilayer) and then get rid of all the other cell components until eventually you end up with pure DNA.

      In Uni we purified DNA from fish eggs in an old fashioned way and I remember that when we finished we ended up with all the DNA from the cells and it literally looked like white tissue paper on the end of a glass rod. There is actually a few meters of DNA in a single cell (you can fit it in your own cells because it is super thin and wound up so tightly), but until you have unwound it all and see it on the end of a glass rod it’s hard to imagine!

    • Photo: Louise Walkin

      Louise Walkin answered on 13 Nov 2012:

      My favourite experiment is actually growing cells. I have to collect cells from tissue so I use a special reagent that loosen the cells from the tissue without damaging them. Then I collect the cells and grow them on a special plate with a liquid covering them. This liquid provides lots of nutrients and makes sure the cells stay alive. Then with the cells in the special environment I can add certain chemicals to them to make them grow faster to produce chemicals that would be released if there was a disease present. The cells act the way they would in the body because they are still alive. Then I measure the the genes that are present to see what has happened in the cells. I get to use lots more exciting techniques for that part! 🙂

    • Photo: Adam Paige

      Adam Paige answered on 13 Nov 2012:

      My favourite experiment is probably sequencing DNA. That means finding out the order of the A, C, G and T chemical letters that make up the DNA molecule. It is the order of these “letter” that explains the instructions to our cells of how to make a specific protein from that gene, and the protein is what does things in our cells (makes the structure of the cells, makes new cells, carries out chemical reactions, etc). If the sequence of the DNA is changed (like a spelling mistake in some writing) then the DNA gene does not make sense any more and it cannot make its protein properly. This is what happens in genetic diseases like cystic fibrosis, and in cancer. So when we sequence DNA we can tell if the sequence is normal or whether it has a spelling error.

      I used to do sequencing by hand (now we use machines much more) and we would detect the DNA “letter” using radioactivity (and it used to sit on a bench just outside my open office door!). When you expose the sequencing to a photographic film the radioactivity makes dark marks so you can see what is happening. The film was covered in these dark marks, and you could tell from their positions exactly what the DNA sequence for that gene was. If it worked well I used to love reading the marks and knowing I was understanding DNA as a result.

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