If you understand how a mini engine works, it's not a great big step to go and understand how a Ferrari engine works

Dr Sean May

But it is precisely because of its simplicity, even anonymity, that Arabidopsis thaliana has been thrust into a lead role in plant biology.

Arabidopsis is an annual flowering plant which belongs to the Brassicaceae (mustard or crucifer) family. Close cousins include the cabbage, broccoli, Brussels sprouts and oilseed rape. Indeed, rape looks very much like a giant Arabidopsis plant.

But unlike its tasty relations, the unassuming weed has not had its genome shoved about by extensive breeding. What you see in the sequence is pretty much what has been there for thousands of years. And that makes it an excellent testbed on which to learn about plants in general.

Weed garden

"It's a very good model precisely because it is a wild plant - it hasn't been modified by human beings over many generations," Dr Sean May, head of Nottingham University's Arabidopsis Stock Centre, told BBC News Online.

Arabidopsis profile

Common names include thale cress or mouse eared cress Belongs to the Brassicaceae (mustard or crucifer) family A few centimetres high Has a rapid life cycle (6 weeks) and prolific seed production Likes a temperate climate and open free-draining ground Frequently found growing on wasteland by carparks and railway sidings

Several species belong to the Arabidopsis genus, but the most well known member and the one most extensively used in research is thaliana.

Arabidopsis occurs naturally throughout temperate regions of the world including Europe, East Africa, Asia and Japan. It is also now found in North America and Australia - probably carried there by animals.

"It actually has adaptations in its phenotypic range that allow it to grow at high altitude, low altitude, where it is warm and where it is cold," Dr May said.

"It'll grow in your garden - you should be able to find it nearby - even in a big city. You can actually grow it in very little soil - just a thimble full. But it has to be said, it's not a very good weed. It's not persistent like dandelion which is difficult to remove."

Hall of fame

Dr May's stock centre will provide plants with specific traits to research labs wanting to investigate some particular aspect of plant biology. The catalogue contains thousands of Arabidopsis plants that have been altered - often in very minor ways.

The plant joins a growing list of completed sequences

"If you understand how a mini engine works, it's not a great big step to go and understand how a Ferrari engine works," Dr May said.

"It is the same with plants. If you have some terms of reference, you can soon see how the components in one plant may fit into another. That's what we have now with Arabidopsis, and we can apply the knowledge to so many other types of plant."

So, little weed or not, Arabidopsis thaliana goes into the genomic hall of fame, along with quite a few viruses and bacteria, yeast, a fungus, a soil worm, a fly, and, very shortly, a human.