Schmalwand, Gänsekraut, Thal's Gänsekresse, arabette rameuse, arabette des dames, wall cress, thale cress, mouse-ear cress, arabide, zandraket, gåsemad, vårskrinneblom, lúdfü, shiro-inu-nazuna, and something in Polish that I’m not going to even try and pronounce. Those are all names for Arabidopsis thaliana – also known as ‘the weed’ - the most popular plant in genetics since Mendel’s peas.
First discovered in the Harz mountains in northern Germany by sixteenth century doctor and botanist Johannes Thal (hence the name, thaliana) Arabidopsis has long been a firm favourite of geneticists who prefer their laboratory subjects to stay still in a pot rather than squeak, fly or otherwise make a nuisance of themselves.
Arabidopsis has been used as a model plant since the 1940s, when German botanist Friedrich Laibach first suggested it might be a good idea. It’s not much to look at – around six inches tall plant with simple white flowers on long stems emerging from a splat of floppy green leaves – but start to mutate its genes and a world of weirdness emerges, revealing vital insights into the molecular nuts and bolts lying behind flower budding, colour and shape; leaf formation; responses to daylight hours, temperature and the seasons; drought tolerance seed formation, disease resistance and much more.
There are other things that make Arabidopsis a handy labmate. It takes only six weeks for them to go from germination to producing plenty of mature seed, making for speedy experiments.
And they can be easily genetically modified using a special type of bacteria known as Agrobacterium tumefaciens. Oh, and they’re really easy to grow in a very small space, which also helps.
Although Arabidopsis isn’t any use as an agricultural crop, it is related to foods like radishes and cabbages. But more importantly, it’s been a vital tool for understanding the inner genetic workings of flowering plants and how they adapt to a changing world – something we’re going to need to know a lot more about in the future.
And finally, a big shout out to some of the other models working hard in the genetics business. There’s E. coli, the hardest working bacterium of them all, from its first discovery in faeces in 1885 to a starring role in molecular biology. Then there’s the yeast that revealed the secrets of the biological engine that drives cell division in all complex life. Snapdragons, or Antirrhinums, have been used as a model to study how plants shape and colour their petals to attract the attention of pollinators, while the see-through embryos of nippy tropical zebrafish have revealed hidden secrets of vertebrate development.
What about C elegans - a microscopic nematode worm made from exactly 1031 cells that appear exactly on cue, making it a handy model for studying cell fate in a developing embryo? And the tadpoles of the African claw-toed frog, Xenopus laevis, have also played an important part in shaping our understanding of the very earliest moments of life, as well as being the first animal to be cloned.
Rhesus monkeys have been used as models for various human diseases, particularly where it’s essential to get as close to a human system as possible, including the development of the polio vaccine. Dogs were used for the discovery and testing of insulin as a treatment for diabetes, which has saved countless human and canine lives, because pets get diabetes too.
And of course, there’s the guinea pig. It may be an unkind way to refer to people taking part in clinical trials, but guinea pigs were the original, err, guinea pigs for the first tests of diphtheria toxin, ultimately leading to modern immunisation against the disease
Then there are some more unusual models. The merits of ferrets have been useful for clinical researchers, as these are the only other animals that seem to catch human and bird flu viruses. And armadillos are used as a model organism for studying leprosy, now known as Hansen’s disease, because they show the same signs of nerve damage as infected humans.
Finally, let’s watch out for the new kids on the modelling block - mathematical models. Scientists are increasingly moving from in vivo to in silico research, creating virtual simulations of cells or organisms inside a computer that can provide valuable insights into biology, as well as running tests and trials in the virtual world before venturing out to experiment in the real one. So if you don’t fancy fruit flies or frogs - and you’re never going to make it on the catwalk - maybe that’s the ideal place to start your scientific modelling career.
References and further reading
Photo credit: INRA, Jean Weber, CC-BY-2.0 via Flickr