Jeffrey Donald Palmer Biography

World of Genetics on Jeffrey Donald Palmer

Jeffrey Palmer has contributed to several research fronts in plant genetics, evolution and molecular systematics. His main, current interest is transfer of genes and introns between genetic compartments in cells and from organism to organism, a process called horizontal gene flow. In plants, those compartments consist of the nucleus, mitochondria and chloroplasts, each with their own DNA genome. Biologists believe that organisms have traded genes throughout the course of evolution. Palmer's research has particularly impacted current understanding of the origin of plastids from cyanobacterial endosymbionts, as well as the organization and evolution of the chloroplast genome. Palmer pioneered the field of chloroplast genomics starting with his graduate work in the early 1980s. By attracting numerous postdoctoral fellows and graduate students, who then established their own programs, Palmer jump-started research on the chloroplast genome and its application to evolutionary questions. According to Robert Jansen, Palmer's first postdoctoral fellow, "he's largely responsible for the field exploding into what it is now."

Palmer's expertise includes molecular biology, genetics, molecular evolution, plant systematics and bioinformatics. Palmer received a B.A. degree from Swarthmore College in 1977, and a Ph.D. from Stanford University in 1981. Following postdoctoral fellowships at The Carnegie Institution of Washington and Duke University, he joined the biology faculty of the University of Michigan in 1984. Palmer moved to Indiana University in 1989, where he is now Distinguished Professor and Chair of the Biology Department.

Palmer has also investigated the organization of mitochondrial genomes and transfer of mitochondrial genes to the nucleus. While such gene flow has been important in the history of all eukaryotes (organisms whose cells contain many discrete organelles), recent transfers have occurred primarily in plants. By sequencing the cytochrome oxidase 2 (cox2) and rps10 genes of plant mitochondria, Palmer's laboratory has identified numerous cases of horizontal gene movement in flowering plants (angiosperms) such as legumes. Based on Palmer's research, it is known that mitochondrial genes moved frequently and recently into the nucleus, and much about how this process occurs. The same can be said for chloroplast genes.

Palmer and colleagues have also probed the origin and horizontal transfer of introns in plants. Introns are extra sequences within genes that are removed from the initial mRNA before protein synthesis. Multiple and frequent horizontal transfers of invasive, group 1 introns into the mitochondrial genome have occurred during angiosperm evolution. The Palmer laboratory has also discovered two separate lineages of plants whose mitochondrial genes evolve up to 1000 times faster than in other plants, due in large part to differences in mutation rate. Palmer has parlayed much of his research on genomes into a clearer understanding of plant evolution. By combining sequence data from mitochondrial, chloroplast and nuclear genomes, his laboratory has dramatically increased the size of available data sets, thereby providing enough information to resolve early branches on the plant phylogenetic tree, including identification of the New Caledonian shrub Amborella as a remnant species of the most basal angiosperm group, or clade. His research team also helped establish the single origin, or monophyly, of the other major group of seed plants--gymnosperms like pines and cycads. It also placed a previously controversial group of plants called theGnetales firmly within the gymnosperms. Lastly, by analyzing mitochondrial introns the Indiana researchers identified relatively simple species called liverworts as the earliest land plants. Palmer has made forays into several other research areas, including the evolution of ancient eukaryotes, the origin and evolution of a kind of intron (called a spliceosomal intron) that interrupts most nuclear genes, and the organization and function of the minimal plastids of apicomplexans--a group that includes non-photosynthetic, disease causing organisms such as Plasmodium and Toxoplasma.

Palmer has taught courses in introductory genetics, evolutionary biology, molecular systematics, and molecular biology laboratory. Palmer's research has been funded primarily by the National Institutes of Health, and the National Science Foundation (NSF). He has published more than 185 articles in a variety of scholarly books and journals. Palmer has also authored important reviews, including commentaries in Nature and Science. Palmer is in demand as a speaker at universities as well as national and international meetings. He has refereed papers for more than 45 journals; served on editorial boards of The Plant Cell, Journal of Molecular Evolution, and other publications; and participated in peer review panels for the U.S. Department of Agriculture. His research has been recognized with prestigious awards including a NSF Presidential Young Investigatorship, The David Starr Jordan Prize, the Arthur F. Thurneau professorship at Michigan, the Wilhelmine E. Key award from the American Genetics Association, and the Class of 1955 endowed professorship at Indiana. He is a member of the American Academy of Arts and Sciences, and the National Academy of Sciences. Palmer credits his success to the many colleagues he has worked with, "I was fortunate to have a large number of exceptional people in the laboratory, especially early on. I want to pay tribute to them, and to the current people in my lab."