Hoxful Monsters

Scientists at Penn State have developed a new computational method that they say will help them to understand how life began on Earth.The team’s method has the potential to trace the evolutionary histories of proteins all the way back to either cells or viruses, thus settling the debate once and for all over which of these life forms came first. “We have just begun to tap the potential power of this method,” said Randen Patterson, a Penn State assistant professor of biology and one of the project’s leaders. “We believe, if it is possible at all, that it is within our grasp to determine whether viruses evolved from cells or vice-versa.”

The new computational method will be described in a paper to be published in a future issue of the journal Proceedings of the National Academy of Sciences. The journal also will post the paper on the early on-line section of its Web site sometime during the week ending 6 September 2008.

Caption: The baobab tree represents one of the most ancient species of life on the planet. In our paper, we investigate ancient and highly divergent proteins, called retro-elements, whose evolutionary histories hold keys to uncovering the origins of life. Our research demonstrates that phylogenetic profiles generated using the Gestalt Domain Detection Algorithm-Basic Local Alignment Tool provide an independent method for estimating the evolutionary histories of retroelements.

Credit: Randen Patterson and Damian van Rossum, Penn State

The team is focusing on an ancient group of proteins, called retroelements, which comprise approximately 50 percent of the human genome by weight and are a crucial component in a number of diseases, including AIDS. “Retroelements are an ancient and highly diverse class of proteins; therefore, they provide a rigorous benchmark for us to test our approach. We are happy with the results we derived, even though our method is in an early stage,” said Patterson. The team plans to make the algorithms that they used in their method available to others as open-source software that is freely available on the Web.

Scientists map out the evolutionary histories of organisms by comparing their genetic and/or protein sequences. Those organisms that are closely related and share a recent common ancestor have greater degrees of similarity among their sequences.

Source : Penn State