Higgs boson, “Evolution in Action” make Science News magazine’s Top 25 for 2012

Two of the top 25 research stories that appeared in Science News magazine in 2012 featured the work of Michigan State University (MSU) College of Natural Science (CNS) researchers.

Wade Fisher, MSU assistant professor of astronomy and physics, was part of a team of international researchers that discovered a new subatomic particle consistent with the Higgs boson, an elusive particle thought to be responsible for giving mass to matter. The Higgs boson discovery was rated by the magazine as the top science story of 2012.

Richard Lenski, MSU Hannah distinguished professor of microbiology and molecular genetics, and a research team working in his lab documented the step-by-step process that allowed bacteria to evolve a new function. That story was No. 23 on the Science News list.

Higgs boson signature simulation

One possible signature of a Higgs boson from a simulated collision between two protons.

The Higgs mechanism was proposed in 1964 by six physicists, including the Edinburgh-based theoretician Peter Higgs, for whom the boson is named. Fisher, who joined MSU in 2009, has been actively involved in the Higgs boson research since 1999, coordinating teams at the U. S. Department of Energy’s Fermi National Accelerator Laboratory near Chicago. In addition to the Fermi research, experiments at the Large Hadron Collider (LHC) located near Geneva, Switzerland, were designed specifically for the Higgs boson search. The combined research efforts resulted in an announcement of the discovery in July 2012.

“What the data are showing us is something new that looks very much like what we expect for the Higgs boson,” Fisher said. “However, we’re being very careful about understanding what we’ve just discovered. Nature has a tendency to surprise us, so the hard work of characterizing this new particle has begun in earnest.”

Finding the Higgs boson is critical to confirming the standard model of particle physics that explains how the universe works. The hunt for the Higgs boson has been compared by some physicists to the Apollo program that reached the moon in the 1960s.

“We’re very flattered to have our research recognized in the media,” Fisher said. “This result is the culmination of decades of work by many thousands of scientists, all with the goal of furthering basic science. We work hard to reach out to the general public with our research, and it is extremely gratifying when the media can help us extend that reach.”

Zachary Blount and E. coli

Zachary Blount led a team of MSU researchers in documenting the step-by-step process in which organisms evolve new functions.

Lenski’s long-term experiment, cultivating cultures of fast-growing E. coli bacteria, was launched in 1988 and has allowed him and researchers in his lab to study more than 56,000 generations of bacterial evolution. The experiment demonstrates natural selection at work. Because the samples are frozen and available for later study, scientist can go back to earlier generations to examine the steps along the way. In this case, the E. coli in one experimental population acquired a new ability to eat a chemical called citrate in the presence of oxygen.

“The change was unusual,” Lenski said. “It wasn’t a typical mutation where just one base pair, one letter, in the genome is changed. Instead, part of the genome was copied so that two chunks of DNA were stitched together in a new way. One chunk encoded a protein to get citrate into the cell, and the other chunk caused that protein to be expressed.”

The research team included Zachary Blount, a postdoctoral researcher in the MSU BEACON Center for the Study of Evolution in Action. Blount wanted to understand the changes that allowed the bacteria to evolve this new ability. In all, 29 genomes from different generations were sequenced and analyzed to find the mutational pieces of the puzzle, which involved a three-step evolutionary process.

“We first saw the citrate-using bacteria at around 33,000 generations,” Lenski explained. “But Zack was able to show that some of the important mutations had already occurred before then by replaying evolution from various intermediate stages. This genomic analysis confirmed that interpretation.

“It’s gratifying when a long-term project pays off, and when the work of talented young scholars such as Zack gets recognized as one of the top science stories of the year,” Lenski added.

The Higgs boson research was funded by the U.S Department of Energy Office of Science, the National Science Foundation and a number of international funding agencies. The genomics-based E. coli analysis was funded, in part, by the National Science Foundation.

For a complete list of the Science News Top 25, visit www.sciencenews.org/article/science-news-top-25.