A mathematical formula developed to explain the constant twisting and turning of DNA within cells is shedding light on the office workers' bug-bear of tangled telephone cords.
The formula also provides information on how much twist undersea fibre optic cables can take before they bend, degrading or ruining signals in the process.
While twisting and turning in telephone or cable cords is a problem, this form of movement is essential to the effective functioning of cells.
Developed by University of Queensland Mathematics Department senior lecturers Dr David Stump and Dr Kevin Gates and the University of Sydney's Dr W Barrie Fraser, the formula is referred to in an article in the April 1999 edition of Scientific American.
"Enzymes are constantly adding and removing loops on DNA strands within cells so that required sections are accessible to the particular cell and the rest is tucked away. For example, a liver cell uses some parts of the DNA - a long, looped molecule of sugar, phosphate and other chemicals - more frequently than others," Dr Stump said.
"Our formula shows that at a given time, up to six percent of turns are taken out by enzymes in order to fit DNA into a cell's nucleus."
But unlike telephone cords or undersea cables, the same enzymes had ingenious ways of detangling DNA if twisting interfered with functioning, Dr Stump said.
"The enzymes have a number of tricks up their sleeves including cutting and rejoining DNA ends to prevent knots," he said.
Twisting and turning in cords whether they be tiny DNA strands or undersea cables such as the major fibre optic cable stretching from Auckland to Hawaii was a natural and unavoidable process, Dr Stump said.
"Nature's laws are designed to minimise energy expended so excessive twisting will eventually result in a bend. Bends or a coiled-up arrangement requires less energy to maintain," he said.
"In the case of undersea cables, the twisting process is exacerbated by currents and if twisting and bending becomes excessive, the signal can be ruined. Heavy copper cables of past years could withstand such pressure.
"In telephone cords, the process is accelerated by people picking the phone up with one hand then flipping the receiver over to the opposite hand and ear."
For more information, contact Dr David Stump (telephone 07 3365 3287).
