Well, this was going to be short but I got distracted explaining science. Mainly I wanted to share the fun thing I did on Wednesday, which was science demonstrating for a bunch of sixth form lads, but I also wanted to share some observations about scientific literacy.
My University department hosted a lab day for the sixth formers from an all-boys Grammar School and I volunteered, some would say stupidly. You know what eighteen year old lads are like, right? Loud, lairy, easily distracted and ever ready to entertain themselves by doing silly things. And you wanted to supervise them extracting DNA from their cheek cells and talk to them about the million dollar laser microscopes? Are you mad?!
Maybe. Probably. Depends who you ask.
Luckily, I actually really enjoy science demos, and the lads were a laugh. They even mostly managed to get the experiments to work! Turns out they only get silly when they run out of things to do and are impatient for the next thing. We had feedback from their teachers the next day saying that the lads had thoroughly enjoyed themselves and were talking about it on the way home. Job well done, I’d say.
The science behind the practical was pretty interesting, given that they were essentially doing a spot of DNA finger-printing, much like forensics labs do with crime scene DNA. They wanted to find out if they had an extra bit of DNA at a particular location so that they could find out how common it was in the population.
Now, there’s a gene, doesn’t matter which, that’s in several sections (exons) separated by bits of DNA (introns) that don’t contribute to the final protein. One intron has the potential to contain a transposon, which is a special sequence that can copy/transpose itself around the genome without causing harm. The gene comes in two varieties, one with the transposon, and one without, the one without being roughly 300 DNA base pairs shorter than the other, a fact which comes in handy later.
Since everyone has two copies of the gene (one from mum and one from dad), they can either have i/ two copies with, ii/ two copies without, or iii/ one with and one without. Some calculations tell us that theoretically 25% of the population should have option 1, 25% have option 2 and 50% have option 3, if the choice is entirely random. By toting up the scores for each option and comparing them to the expected percentages, the lads were able to tell whether or not the transposon-containing version of the gene was getting passed down at random. While not of life-changing significance in this case, this type of information can be very helpful where hereditary diseases like sickle cell anaemia are concerned.
But first, to get to the stage of knowing which combination they had, the lads had to do a lab practical that came in three parts. First they had to extract their DNA using a salt solution and some clever little gel beads that suck up DNA. Then they had to do something called the PCR reaction to make lots of copies of the bit of the gene that may or may not have contained the transposon. Finally they had to separate the short (transposon-lacking) and long (transposon-having) versions out by size, by running the DNA on a gel . We say ‘run’ because the gel (a 3D rectangle of a jelly-like substance that is holey a like a sponge on the molecular level) sits in a salt bath, through which we run a high voltage electric current. The shorter DNA bits travel further down the gel because they can squeeze through the holes more easily than the longer bits. You take a photograph of the gel at the end under UV light and the DNA shows up as bands in the gel, like so:
I love gels for their simplicity and because you either have the result you want or you don’t. If you’ve included the right controls you can work out why it didn’t work. Unless you got nothing at all from your PCR! In which case the problem solving gets tricky and you have to start again.
So yes, for the most part the lads’ PCRs worked! They were impressed with themselves and rightly so, since it was the first time they’d done anything like this using current scientific techniques. Watching them do the practical for the first time also opened my eyes to just how much I learned at undergrad and how steep the learning curve was.
Not only is there the practical side to the learning curve – how to handle a pipette, how to pick up pipette tips without using your fingers, how to load samples into a gel (trickier than it looks!), how to make sure you’ve got the right controls etc., there’s also the vocabulary and background understanding. Words they didn’t know that to me are everyday terms included “vortex”, “bijoux”, “centrifuge” and “supernatant”. To vortex is to mix the sample at high speed on a vortexer, kind of like whisking something up but without having to touch it. Bijoux are little plastic screw-top cylinders that hold about 5ml of liquid. To centrifuge something is to spin it at high speed so the heavy stuff settles at the bottom of the tube, like those funfair rides that you stand up in that spin round really fast and pin you to the wall behind you using centrifugal force. Once you’ve centrifuged something, you get the pellet of heavy stuff at the bottom, and a liquid, the “supernatant” on top.
Knowing the terminology however doesn’t matter in the grand scheme of things. Neither does lacking the practical skill set that allows you to do the kind of molecular biology I do every day in my PhD. That’s what you do an undergrad degree for, that’s why you spend hours a week in the lab doing practicals and that’s why many universities offer a 3-month lab project in the final year. Most of a PhD’s first year is spent getting to grips with the techniques you’ll need later. Any actual results that make it into the final thesis are a bonus.
The thing that does matter is the background knowledge of the biological techniques and methods, and most importantly the understanding of what DNA, genes and proteins actually are. If you don’t have a grasp of these basics then pretty much all of the medical/genetic research that makes it into the media is going to pass you by. Something that frustrates me no end is when a newspaper publishes an article about a scientist who’s discovered, say, “a gene involved in diabetes”…”which could lead to a cure in 10 years time”. Just because a gene with a link to a disease has been discovered, doesn’t mean a cure or a treatment is imminent. The timescales involved in biological and medical discoveries that are relevant to diseases are MUCH longer than most people realise, including the members of government who kindly give us the money to do the research in the first place. It’s similar to how the cure for HIV/AIDS is just around the corner, but keeps getting pushed back by another five years every few years! Doing research takes a lot of time. Getting good, useful results takes even longer. And Supervisors and Primary Investigators forget it too, especially if they’ve not been in the lab in a few years.
Given that I’ve been immersed in academic culture for nearly six years now, I’d forgotten just how much I’ve learnt in my time in the ivory tower, and just how little the average person knows. The things I take for granted *are* complex and took three years ofdedicated learning to gain. I took a look at the A-level syllabus before the practical for
the Sixth Formers and wow, I didn’t realise how little they teach A-level biologists. They teach enough that a new undergrad will have a vague idea of what’s going on. They’ll have an appreciation of protein structure, DNA synthesis, genes and basic genetics, and basic cellular structures but that’s it. They don’t teach the PCR reaction and how it underpins just about every single cloning reaction, and they don’t differentiate between the cloning of whole genomes into new organisms (Dolly the Sheep) and cloning of a single gene into a bacterium, which explains a lot of the hoohaa about GM crops.
The worst thing is that the A-level biologists account for a fraction of 18-yo school leavers, and those 18 year olds were less than half of their cohort. My Sixth Form had ~60 students in it but my school year had 180 students in it at Year 11. Some of those went to other Sixth Forms or Colleges but, given that ~30% of the UK population doesn’t even get 5 GCSE passes at C or above, that’s still a significant portion of the population who have no science training beyond basic GCSE, and even those that do will have little biological knowledge.
Ultimately, what this demonstrating event taught me is that “public engagement” is vital. It also reminded me that I have learned a hell of a lot during my time at university and that I need to simplify my science a lot more than I currently do when I’m explaining it to non-biologists. Having good analogies and simple summaries on hand is majorly important and finally, getting involved in public engagement can be really good fun!