Do worms get old?

by Sophie Gilbert

I have recently finished my PhD in the Department of Biochemistry at the University of Oxford, working under the supervision of Alison Woollard (Royal Institution Christmas Lecturer in 2013). I specialised in a species of very small (1mm long) nematode worm called Caenorhabditis elegans. These animals may sound exotic, but in reality, they are found at the bottom of nearly every garden in the world. Intriguingly, the worms’ characteristics vary according to their nationality: those found in Hawaii tend to be more promiscuous than their British counterparts, and Australian worms contain a mutation that not only makes them more social, but also increases their alcohol tolerance.

In this short video you can see worms crawling around under a dissecting microscope, which is how we visualise them. The biggest worms you can see are, in fact, only 1mm long! The worms eat bacteria (E. coli, non-pathogenic), which is growing in this petri dish full of bacteria.

The great thing about these worms is that they’re in many respects like small humans: they have a nervous system, a gut, muscles, skin, stem cells, and in addition they sleep and even grow old in much the same way we do. How do you spot an old worm? Like us, they get wrinkles and slow down, don’t move as much, and their organs start to fail. However, there are many advantages of looking at all these systems and processes in worms rather than humans – they only live for around 20 days (no waiting around for them to slowly age), they lay 300 eggs in the first few days of adulthood (there are always lots of them to look at), and they’re much smaller, simpler and easier to manipulate. This is not to mention that most humans would probably object to being grown in a lab. 

Recently, I volunteered to bring the worms – and my colleagues – to Super Science Saturday at the Museum of Natural History, during which we explained to families how we use C. elegans to study the genetics of ageing: parents tend to show a particular interest in this topic. Until relatively recently, it was believed that ageing was an inevitable consequence of living – an unfortunate response to environmental stress and general wear-and-tear. Remarkably, it has now been discovered that many aspects of ageing are actually encoded in our DNA: changing just one gene can have a drastic effect, either shortening or extending our lifetime. We can use worms to explore this effect – and we can also use worms to discover new genes and processes that underlie healthy ageing.

Being able to demonstrate this rapidly expanding research field – as well as the worms themselves – to the public, especially to children, allows people to learn enough about biology to appreciate both its social and economic value, as well as giving us as scientists an invaluable insight into why our research is important. Next time, however, I might include a new warning sign for the microscope: “Look, don’t lick!”