Barbara A. Schaal

Barbara A. Schaal

Abstract

Biodiversity, Genetic Diversity, and Conservation

Plant conservation biologists are concerned with biodiversity at three levels: community diversity, species diversity and genetic diversity. Both theoretical and experimental studies have demonstrated the importance of maintaining high levels of genetic diversity within species for long-term survival. Loss of genetic diversity can result in loss of plant fitness due to increased homozygosity and fixation of alleles with deleterious effects. Likewise, loss of genetic variation can reduce the evolutionary potential of a species to adapt to different environments. Mead's milkweed is a threatened prairie plant of the midwest United States. Both population numbers and sizes have been severely reduced due to agriculture. An analysis of genetic variation within and among populations of Mead's milkweed by Random Amplified Polymorphic DNA measured the number of individuals and their clonal structure. Some populations of Mead's milkweed contain few genotypes. No seeds are produced in several of these populations due to self-incompatibility. To assure the long-term survival of Mead's milkweed, conservation and restoration efforts require the infusion of multiple genotypes to restore seed production.

Biography

Barbara A. Schaal is the Spencer T. Olin Professor of Biology at Washington University and a research associate at the Missouri Botanical Garden. She received her B.S. from the University of Illinois at Chicago in 1969 and her Ph.D. from Yale University in 1974. Dr. Schaal's research interests range from plant population genetics to macroevolution and systematics. Current studies include molecular phylogeny reconstruction in several plant groups using nuclear and chloroplast DNA sequences. Other work examines the quantitative genetics and molecular evolution of disease resistance genes in plants. Several studies address issues in conservation biology, including the loss of genetic variation in isolated populations, the genetics of invasive plants, and the origins and biodiversity of the tropical crop, cassava. Schaal is currently an associate editor Conservation Genetics and The American Journal of Botany. She serves as chair of the Scientific Advisory Council of the Center for Plant Conservation and as a member of the board of trustees, Missouri chapter of The Nature Conservancy. She has served as executive vice president of the Society for the Study of Evolution, president of the Botanical Society of America and chair of the Department of Biology, Washington University. She is a fellow of the American Association for the Advancement of Science, a John Simon Guggenheim Fellow, and a member of the U.S. National Academy of Sciences.

Relevant Publications

Olsen, K. and B.A. Schaal. 1999. New evidence on the origins of cassava: Phylogeography of Manihot esculenta. Proc. Natl. Acad. Sci. 96:5586-5591t.

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