There’s a recent letter to the journal Nature, which explores the age of single point mutations in the human genome. This data comes as part of a large DNA sequencing project, funded by the National Institutes of Health Heart, Lung and Blood Institute, which focuses on exons within the human genome.
Exons are kind of like the business end of the genome, meaning they make up the genetic code for proteins that play a major role in the development and everyday control of your body. That is not to say, however, that these are the only necessary or even the most important parts of the genome. As research progresses, biologists are learning that more and more of the DNA between these exons dictate where, when and how much of a protein will be made – regulation critical to life. But I digress.
The study, headed by the Akey group at the University of Washington, Seattle, examined the exomes (the part of the genome formed by exons) of 6,515 individuals from European and African decent. What’s the reason for looking at all of these exons? To compare the occurrence and position of small mutations across the genome. In doing so, the researchers were able to build a tree for the age, and therefore evolution, of mutations in our genome – specifically deleterious ones. And since deleterious mutations are sometimes correlated with disease, they were able to track, in a sense, the evolution of certain diseases.
In a nutshell, the study finds that most deleterious mutations are younger than 5,000 years old and that this can most likely be attributed to an explosion in the human population around that time. After all, the more genomes you make, the more you increase the chances for new mutations. The study also found that the surge of new mutations included among others, those responsible for premature ovarian failure, Alzheimer’s disease, coronary artery atherosclerosis and hereditary spastic paraplegia.