Oct. 15, 1998
Vol. 18, No. 2

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    Packard Fellowship awarded to professor studying gene fragments

    Manyuan Long, Assistant Professor in Ecology & Evolution, is one of 24 national recipients of the David and Lucile Packard Fellowship for Science & Engineering.

    The fellowship, which provides $625,000 over the course of five years, is awarded to professors to support their basic research in the fields of chemistry, biology, physics, mathematics, astronomy and computer science.

    Long studies how genes evolve, using molecular techniques and computer software to search for new genes and to compare and contrast thousands of genes at a time.

    Long, who has been studying genetics since the late 1980s, said many new genes are created 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 gene fragments to recombine and create new genes without overlapping, said Long. The introns act as leaders that are later spliced out, bringing the fragments together to form a new gene. These early 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, allowing organisms to adapt to new environments," Long explained.

    Over the past decade, Long's theory slowly gained support from notable scientists, but no one had ever found a gene created through shuffling. Such a discovery was made in 1993, when Long discovered the gene jingwei.

    Reflecting his Chinese heritage, Long named the gene after an emperor's daughter in an ancient legend.

    According to the story, Jingwei drowned in the East China Sea and was reincarnated as a beautiful bird. The bird flew about dropping stones and wood in an effort to fill the sea to prevent others from drowning.

    "We used the name jingwei because this gene avoided the usual fate of the processed gene (death) and was 'reincarnated' into a new structure with a novel function," Long explained.

    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) cells diverged. Because bacteria do not contain introns, others believe introns developed after the divergence of prokaryotes and eukaryotes.

    Long said he believes bacteria lost their introns to facilitate faster replication. Bacterial cells 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.

    He and his student assistant, biology undergraduate Michael Deutsch, also observed the correlation between the size of an organism's genome and the percentage of the genome made up of introns.

    "Organisms with larger genomes have more of their genetic material devoted to introns," said Long.

    Smaller organisms, like bacteria, need to replicate quickly so 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, China, in 1982. He received his M.S. and Ph.D. in genetics from the University of California, Davis, in 1990 and 1992, respectively. Long did postdoctoral work at Harvard University before coming to Chicago in 1997.

    The David and Lucile Packard Foundation is a private, family foundation created in 1964 that provides grants to not-for-profit organizations for programs in the arts and sciences.