Manyuan Long, Ph.D., assistant professor of ecology and evolution at the University of Chicago, is one of the nation's 24 recipients of the David and Lucile Packard Fellowship for Science & Engineering. The Fellowship, which provides $650,000 over the course of five years, is awarded to young professors in the fields of biology, chemistry, physics, mathematics, astronomy and computer science to support basic research.
"I'm very excited about the award," he says.
Long studies how genes evolve. He uses sophisticated computer software to compare and contrast thousands of genes at a time.
"This is the best time to be doing this kind of research because of the new information and technologies we have thanks to the Human Genome Project. I could not have done this work 5 years ago," he explains.
Long believes that new genes arise through the shuffling and mixing of existing genes or gene fragments. "Junk" DNA, or introns, the stretches of genetic material that appear to have no real function, actually allow the gene fragments to recombine and create new genes without overlapping, says Long. The introns act as leaders which are later spliced out, bringing the fragments together to form a new gene.
Remnants of the earliest gene pieces have been detected in fruit flies.
"We think that early in evolution, a few genes existed that could shuffle and recombine to make new genes to let organisms to adapt to new environments," Long explains.
Though Long's theory slowly gained support from notable scientists over the past decade, no one had found a gene created through shuffling until 1993 when Long announced his discovery of the gene jingwei.
Reflecting his Chinese heritage, Long named the gene jingwei after an emperor's daughter in an ancient legend. Jingwei drowned in the East China Sea and was reincarnated as a beautiful bird that flew about dropping stones and wood in an effort to fill the sea to prevent others from drowning. "We used the name jingwei," Long says, "because this gene avoided the usual fate of the processed gene (death) and was "reincarnated" into a new structure with novel function."
Long is now busy accumulating evidence in support of the "introns-early" theory, which suggests that introns existed before prokaryotic (bacteria) and eukaryotic (plants, animals, etc.) cells diverged. Others believe that introns developed after the divergence of prokaryotes and eukaryotes because bacteria don't have introns.
Long suspects that bacteria once had introns and lost them millions of years ago to facilitate faster replication. Bacterial cells can mutate rapidly to adapt to new environments and can replicate as fast as once every 30 minutes. If they had to copy long stretches of useless DNA every time they divided, their growth rate could be nowhere near as rapid.
Long also cites the correlation between the size of an organism's total genome and the percentage of the genome made up of introns. "Organisms with larger genomes have more of their genetic material devoted to introns," he says. "Smaller organisms like bacteria need to replicate quickly so that they can respond to environmental stresses. Larger organisms rely less on rapid replication to survive changes in the environment and have accumulated more introns over time."
Long received his B.S. and M.S. in plant genetics from Sichuan Agricultural University in Ya'an, China in 1982. He received his M.S. in 1990 and his Ph.D. in genetics in 1992 from the University at California, Davis. He did postdoctoral work at Harvard University before coming to the University of Chicago in 1997.
The David and Lucile Packard Foundation is a private family foundation created in 1964 by David Packard (1912-1996), co-founder of the Hewlett-Packard Company, and Lucile Salter Packard (1914-1987). The foundation provides grants to nonprofit organizations for programs in the arts and sciences.