A team of scientists based at San Diego State University, the University of Chicago, and the University of South Florida have analyzed all sequence data available in public databases from complete genomes and environmental community genomes, and found out that jumping genes (known as transposases) are nature's most abundant genes. Textbooks teach us that the enzyme that fixes carbon dioxide during photosynthesis may be the most abundant enzyme on earth, but this research disputes that theory. "We were expecting that other essential genes like DNA polymerase to be at the top of the list. The finding that transposase genes, known as jumping or selfish genes, often thought of as junk DNA, are the most prevalent genes in nature's ecosystems came as a surprise," says lead author, Dr. Ramy K. Aziz, a lecturer from Cairo University-Egypt currently training at Dr. Robert Edwards’ laboratory at SDSU. Aziz follows up: "Before this study, it was known that transposable elements make up to 40% of the human genome; however, there has not been a comprehensive assessment of such genes in different ecosystems. Now we know that almost every ecosystem sampled to date has a substantial number of these genes, which are known to accelerate mutation and diversification processes, thus driving evolution of different organisms."
Dr. Robert Edwards, assistant professor of computer science and biology at SDSU and the team leader, comments: "We presented these data in different meetings, and when we ask scientists to guess the top 3 genes, they rarely make the right guess. It has happened only once. These genes are so ubiquitous in genomes that they are not noticed. They are able to move from spot to spot, causing mutations and rearrangements that are often detrimental but that occasionally help an organism survive." Dr. Edwards emphasizes that such analysis was only made possible because many scientists generously share their data as soon as they get them. Instead of storing their data in private databases, for example, they submit their data to RAST and MG-RAST–web repositories developed by Dr. Edwards and colleagues at the Argonne National Laboratory in Illinois. The analysis of these billions of DNA letters is computationally intensive and took several months to finish, it is aided by some of the world’s fastest computers at Argonne, and new and efficient code written by Argonne and SDSU scientists.