Friday, 9 December 2011

Beep! Beep! Defining the Fungal Barcode for Aspergillus

Many species of fungi including Aspergillus are very difficult to distinguish from one another. They can lack distinct structures, many having very simple forms and many lack sexual forms thus removing one long standing method used to distinguish species from each other i.e. their ability to interbreed.

A more modern way to distinguish species is to look at their DNA sequence. We have started to sequence entire genomes (the complete DNA sequence of an organism) but as yet this is still quite slow and requires a lot of effort and money to carry out - there has to be a quicker, cheaper, more flexible way to tell one species from another.

The ability to distinguish Aspergillus species is very important for several reasons including:

  • to distinguish between medically important (i.e. potentially dangerous) and unimportant (safer) Aspergillus species in the air, in a clinic, in homes, in our lungs
  • to distinguish between species likely to produce mycotoxin when growing on food or growing in damp buildings
  • to improve taxonomy for scientific identification, speed up research, we will get a better idea of the numbers of different species in our environment e.g. in our drinking water
DNA barcoding is a quick, cheap method than can be used on large numbers of samples in a short time. It is a powerful 'quick screen' once you have identified a series of short DNA sequences that are unique to each  species. Short DNA sequences are easy to work with and require minimal equipment to look at, all of which would be portable or available in a small laboratory at little cost - this makes this technique attractive to people working away from large laboratories, and in poorer countries - in other words the vast majority of the world.

Fungal barcoding is an ongoing research effort but a recent news report suggests that breakthroughs have been made in the search for unique short sequences in fungi including Aspergillus species. Reports at the recent International Barcode of Life conference in Australia suggest that an area of the genome of most fungi contains DNA sequences that are unique in most species. More work is yet to be done to make this discovery useful to us all but this is a big step forward.

No comments:

Contact us at