Genome sequencing

The human genome (the entire DNA code of a human) was first mapped fully in 2003. When it was started in 1990, it was envisioned that by sequencing an entire genome we would rapidly gain an understanding of the workings of genes and quickly start to develop new medicines and techniques to deal with not just genetic diseases but also various disorders and pathological conditions.

As with many discoveries in science, the immediate benefits of knowing the genome have taken a while to filter through into useful work. One interesting effect is that it is now possible to identify genomes of other organisms much more rapidly, as the technology has advanced. Published this week in the magazine Nature was a study that sequenced the genome of the bacteria responsible for the Black Death, Yersinia pestis. It turns out that the genome is not too dissimilar to modern strains of the bacterium.

Scientists extracted the DNA from skeletons removed from medieval burial grounds. It is of interest particularly to try and identify why certain strains of pathogen seem to cause so many more problems and are so infectious (the Black Death killed an estimated 30-60% of the population of Europe at the time). It is also instructive in showing evolutionary pathways for bacteria, allowing scientists to trace back from today’s descendents and compare DNA sequences. As more and more organisms are sequenced, we are able to gain a better understanding of the similarities between organisms and see further into what comprises ‘life’.