Japanese scientists have developed a probe that could help detect genetic diseases.

Hiroyuki Asanuma at Nagoya University and co-workers created the probe to recognise changes in DNA structure called polymorphisms. Deletion polymorphisms - where one or more nucleotide bases are missing - have been linked to genetic diseases. 'Developing methods for the detection of polymorphisms is currently an important theme in personalised medicine,' explained Asanuma.

To form their probe the group attached fluorescent pyrene units to short nucleotide chains called ODNs (oligodeoxyribonucleotides). These ODNs can bind to DNA. The pyrene groups were slotted either side of one nucleotide. This meant that when the probe bound to normal DNA the pyrene units were held apart by a base pair and only monomer fluorescence was seen. If the DNA contained a deletion polymorphism the pyrene units were forced together, producing a different signal. By changing the distance between the pyrene units, the team were also able to use their method to detect multiple base deletions.

Bruce Armitage of Carnegie Mellon University, US, said that the probe is significant. 'The assay offers an efficient way to detect deletion mutations,' said Armitage.

Asanuma now wants to extend this work. 'In the near future, a new multi-functional probe that can detect both single nucleotide polymorphism and insertion/deletion polymorphism simultaneously will be developed,' said Asanuma.

Rebecca Gillan