• Question: How are you able to detect cells which we don't know about and try to predict their properties?

    Asked by MandMMoos to Stewart, Miriam, Marton, Laura, Kathryn, David on 12 Nov 2018.
    • Photo: David Ho

      David Ho answered on 12 Nov 2018:

      I study a particle that we’ve never seen before called a “magnetic monopole”. All the magnets we’ve ever found in nature have a North and a South pole, and you can’t split the two — if you cut a magnet in half you get two more magnets, each with North and South poles. However, as you can probably tell from the word, a “monopole” would just be a North or a South pole on its own.

      Even though we’ve never observed one, if it exists we know it has certain properties. A magnetic monopole, for example, definitely has to be magnetic! So what I do is I look at equations that apply to all magnetic particles and try and use them to show how we might produce monopoles. For example, if monopoles are light (if they have a low mass), we should be able to produce them in particle collisions. Because we’ve done particle collisions and haven’t ever made one, we know that they must be heavy! It turns out that using techniques like this we can tell a lot about particles we’ve never seen!

    • Photo: Stewart Martin-Haugh

      Stewart Martin-Haugh answered on 13 Nov 2018:

      I don’t look for cells in the body: what I’m looking for is tiny (smaller than an atom) particles. We have equations that say what sort of signal they should leave in a detector. Using computers we can check if the particles in our detector look like new particles or ones we already know about.

      A similar process happens when chemists are trying to invent new drugs – they have chemistry equations that say how chemicals should interact with cells in the body, and they can run the equations on computers before testing them with real cells. This is much cheaper than having to do real experiments each time, so it’s easier to find new drugs.

    • Photo: Marton Olbei

      Marton Olbei answered on 13 Nov 2018:

      There is a whole field about this called metagenomics! What they do is take an environmental sample (let’s say pond water) and then try to sequence the genome of _everything_ found in that sample. This means that they determine the order of the DNA sequence of every living thing what lived in that sample. This is unique to every species, and we can then determine what lives in there. When we find something that we haven’t seen before we can guess what it’s like based on the differences (what it’s closely related to, what kind of genes it has).
      A big issue with this is that you are not seeing the actual cells, you are just seeing the “blueprints” of one.