Vancouver, Aug 11 - Extracting DNA from very small or heavily contaminated samples won't be a difficult task any more, according to the latest research.

Canadian researchers at the University of British Columbia here say they have developed a new technique to extract DNA and RNA (ribonucleic acid) from even small or heavily contaminated samples to help forensic investigators and molecular biologists.

RNA is similar to DNA barring a few structural differences.

'By exploiting the physical traits of DNA - electric charge, length and flexibility - we have been able to extract DNA from samples that would otherwise not produce enough clean DNA for analysis,' biophysics professor Andre Marziali said.

Extracting DNA by conventional methods - which rely on the molecules' chemical properties - has proven challenging when there are only trace amounts of DNA or when the source sample has contaminants with similar chemical traits, the university said.