Question: how do you know that DNA is DNA when you see it (what can you see it?)


  1. Hi ally11.

    Most of the work I do I don’t actually get to see the DNA. I’m usually working with clear liquids and use chemicals which react with the DNA to know that its there. But there are some ways to visualise DNA.

    I can run DNA on a gel, which is a bit like jelly but stronger, it has little tiny holes in it which are too small for us to see but DNA can fit through. The speed the DNA travels is based on size so I can separate out what I have. When we do this I also include a dye with binds to DNA and lights up under UV light. So when my gel is finished separating the DNA i can put it under UV light to visualize the DNA. I also send samples off for sequencing so I know whats there when I get the sequence back.

    But probably the prettiest way to see DNA is under a fluorescent microscope. You can stain DNA and proteins with different coloured fluorescent dye an then look at it. When a cell is just sitting there going about its normal functioning, you generally see a mess of DNA. But when the cell is dividing, the chromosome condense and you can see them looking like strings in patterns being pulled apart as the cell divides. Pretty cool!

    Have a look at some of these sites for some nice images!