Walking the Chromosome This month, scientists announced they'd identified the gene which causes the disease cystic fibrosis.
Professor Lewis Wolpert reports on the 10-year race to discover the gene.
How Green Is Our Garden? Modern pesticides deliver ready supplies of cheap food. But the other legacy is toxic residues in our food and water. The Guardian's James Erlichman looks at whether science offers realistic alternatives.
Nature Bites Back
It's carried by a tick and causes a disease now being found in Britain and Europe. In the USA people are avoiding the woods for fear of the most serious infectious epidemic since AIDS.
Professor Durland Fish asks: 'Is Lyme Disease the price we're paying for going back to nature?'
Producers DANA PURVIS and PRATAP RUGHAN1
Executive producer DAVID PATERSON Series producer JANA BENNETT