Pages from the first human genome
When the human genome is printed out in a series of books, the
DNA sequence fills more than 100 books. Image Courtesy: Russ
London's photograph of the Human Genome in the "Medicine Now"
room at the Wellcome Collection in London.
Six years ago this week, hundreds of researchers were awaiting the publication of their landmark study that focused on one thing ⎯ the human genome. In their study, the researchers described the complete sequence of human DNA, the order in which 3 billion genetics bases, or letters, appear along a strand of DNA.
While reports of the study reached a worldwide audience, not everyone could conceptualize the DNA sequenced ⎯ after all, DNA is invisible to the naked eye. Thus, in the spirit of science education, several clever analogies and images were conjured up to help describe the sequence of human DNA, or genome.
In the photo above, the series of binders on the bookshelf display how many pages it would take to hold the 3 billion letters of the human genome. If a person were typing out the human genome at a relatively quick rate for eight hours every day, it would take more than 50 years to complete the job. However, when a cell replicates, it only takes an average of about eight hours to copy the entire sequence.
Although sequencing the genome was a major step toward getting a grasp on our own DNA, there is a lot more to learn. Current estimates predict that only 5% of the 3 billion DNA letters actually produce functional units, such as the genes that encode a cell’s proteins. Since the genome's completion, researchers at the Broad Institute have been using the sequence of the human genome as a tool to pinpoint all of the functional bits of DNA, genetic mutations that cause disease, as well as the normal amount of genetic variation between individuals.