Keck Graduate Institute has announced that Dr. Animesh Ray, director of KGI's PhD program, has published a paper that sheds new light on the evolution of moveable genetic elements, or "jumping genes."
"We have known for some time that some genes can move from one place to another within the genome," said President Sheldon Schuster, PhD, KGI's president. "Dr. Ray's research provides evidence that this movement of genes does not cause instability at the point from which the gene moves. This discovery has important implications for our understanding of molecular evolution and genetic research involving plants, including genetically modified crops. These findings take us closer, for example, to more precisely predicting the changes a drought-resistant jumping gene from one plant put into another may cause to the DNA."
Using the plant Arabidopsis thaliana, Ray and his students studied the "footprint" that is left behind when a jumping gene moves to another locus. They devised a test for examining these footprints that revealed a mechanism for the broken DNA at the launching pad region (the original location of the jumping gene) to join together to repair the vacant area. The results indicated that the DNA repaired itself in a manner that did not produce drastic abnormalities.
Ray characterized the genomic DNA as "smart" for repairing itself in a manner that doesn't produce drastic abnormalities. He also said that the process of repairing is "ancient" because the mechanism appears similar to that used by the immune system of mammals. Ancestors of plants and mammals diverged early in evolution, at least 1.5 billion years ago.
The findings of Ray, his students Marybeth Langer and Lynn Sniderhan from the University of Rochester and co-author Ueli Grossniklaus, professor at the University of Zurich, were reported in the paper "Transposon Excision from an Atypical Site: A Mechanism of Evolution of Novel Transposable Elements." The work extends theories of the renowned cytogeneticist Barbara McClintock, who originally discovered moveable genetic elements. Ray's research also follows on the work of molecular geneticist Enrico Coen who has examined implications of moveable genes in plants and first proposed a similar mechanism of chromosome healing.
Citation: Langer M, Sniderhan LF, Grossniklaus U, Ray A (2007) Transposon Excision from an Atypical Site: A Mechanism of Evolution of Novel Transposable Elements. PLoS One 2(10): e965. doi:10.1371/journal.pone.0000965
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