The work will stand for six months

Jason Middlebrook's The Geology of Biology measures three metres by 113 metres (10 feet by 370 feet). The artist hopes the work will make a windswept, unlovely and traffic-choked area of the city "a little more visual and complex".

Pedestrians and semi-stationary bus passengers will have six months to see the work, commissioned by the research-funding charity the Wellcome Trust to surround the site of its new headquarters.

"What it's all about for me is for people to contemplate what's beneath the surface, not only the ground but the skin," Mr Middlebrook told BBC News Online.

Giant DNA

"The area reminds me of so many cities I've spent time in in the United States - a bit drab. I wanted people to recognise that there could be some beauty down there," he said.

We believe that art, like science, should be accessible to everyone

Dr Mike Dexter Wellcome Trust director

The work depicts giant DNA strands, human cells, plant cells, brains, sperm, eggs, roots and protozoa.

Mr Middlebrook, based in New York, said that he wanted to make a connection between geology and biology and suggest a link between the layers below ground and the layers beneath the skin.

"People often think it's just blood and bones, but there's a lot of information there that has a function and a beauty," he said.

More of his work is being shown at the Wellcome Trust's Two10 Gallery, opposite the site.

Accessible art

The Wellcome Trust's director, Dr Mike Dexter, said that the trust believed that art, like science, should be accessible to everyone.

The largest piece of public art in London

"The Human Genome Project is about humankind, and we hope that through this public artwork we will not only brighten people's day, but inspire passers-by to think about the broader significance of science in our daily lives," he said.

The Two10 Gallery says that the work is part of a "new wave" of genome-inspired work that includes the conceptual DNA portrait by Marc Quinn of genome scientist Sir John Sulston in the National Portrait Gallery.

The Wellcome Trust funded the HGP work of UK scientists, who decoded about one-third of the chemical "letters", or DNA bases, that make up the human genome.

Marc Quinn (r) with his DNA portrait of Sir John Sulston