Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Evolution of Life Cycle in Land Plants

Yin-Long Qiu

Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA

Abstract

A complete life cycle of sexually reproducing eukaryotes consists of a diploid phase and a haploid phase. The relative length of either phase varies greatly among different lineages of eukaryotes. Under a recently reconstructed molecular phylogeny of streptophytes (charophyte algae and land plants), we examined the pattern of life cycle change in Characeae, liverworts, mosses, hornworts, lycophytes, monilophytes, and seed plants. We found that the life cycle of land plants had evolved in a direction of continuously expanding the diploid phase while reducing the haploid phase. In other words, evolution of land plants can be viewed as a series of events of delaying meiosis after fertilization and reducing mitosis after meiosis. Adaptive significance of this life cycle change will be discussed, and molecular mechanisms underlying this life change will also be explored.

Yin-Long Qiu

Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA

Biography

Yin-Long Qiu is a plant evolutionary biologist specializing in the study of early evolution of land plants. He and his lab have engaged in the following areas of research over the last 20 years: reconstructing the early land plant and basal angiosperm phylogenies, investigating mitochondrial genome evolution in early land plants, and studying the origin and evolution of genetic mechanisms underlying evolution of characters that confer adaptive advantages to plants during some major evolutionary niche transitions, such as plant-mycorrhizal fungus symbiosis, gravitropism and stem cell initiation during the origin of root, and delay of meiosis initiation in the life cycle of major lineages of early land plants. He is currently an associate professor in Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, USA (email: ylqiu@umich.edu).