Optical technology closes in on goal of $1,000 whole-genome sequencing
Charles Choi, Scientific American
The exorbitant cost of decoding an individual's genome dropped in 2005 from $20 million to a tenth of that amount. George M. Church of Harvard Medical School and his colleagues at Harvard and Washington University in St. Louis, developed a method for determining DNA sequence using commercially available equipment.
The method may help achieve the goal set by the American government to reduce the process to $1,000 by 2015. Experts claim that at such a price, decoding the genome of each of us for medical purposes will become practical. The "do-it-yourself" method developed by Church's research group is based on a combination of readily available and relatively cheap microscopes with fast digital cameras
. 454 Life Sciences of Branford, Connecticut has developed a similar method that combines cameras and microscopes to decode DNA sequences, but uses a different light emission technology than Church's. Conventional sequencing methods generally use bacteria to replicate copies of the desired DNA molecule. Both new methods instead use tiny beads to capture the DNA and enzymes to replicate it. Church's method is about 20 times faster than routine sequencing methods, and costs $140,000. The 454 method has about 100 times the throughput of routine sequencing at a cost of about $500,000 per machine.
Unlike these optical methods, the methods used to determine the sequence of genes today are based on electrophoresis, a method that separates molecules according to their size and refreshes them using an electric field. H. Kumar Wickramasinghe of the IBM Research Center in Elmden and his colleagues developed a method that combines electrophoresis with an atomic force microscope (AFM), which scans the surface using very pointed sensors. The invention can sort DNA segments at a speed 100,000 times greater than normal electrophoresis, but it is only effective for short segments that are 40 nucleotides in length at most. The researchers note that their work can not only speed up the decoding of DNA sequences but also place molecules on surfaces with unprecedented precision.
One response
very interesting. Well done. It is encouraging to hear that within two years the cost has dropped from twenty million dollars to a hundredth (not a tenth!!) of that.
As someone who works with 16S sequences in bacteria (1600 nucleotides in size soon) I can say that in order to obtain such a sequence I spend an average of 4-6 dollars. Of course, the methods are electrophoresis and microbiology - so it takes at least 5 days until I can get the sequence. The new developments sound very promising and will give a strong boost to the field. We look forward to further progress soon.