Mechanism of neocentromere motility and meiotic drive in maize

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The predictive power of genetics rests on the concept that all genes have the same chances of being passed on to offspring. This is Mendel's first Law of Segregation. The goal of this project is to better understand the rules of genetics by studying a rare exception that violates this fundamental tenant. By using maize as the study species, we can visualize genetic segregation with precision, as the chromosomes are large and easily visualized, and the transmission of genes can be seen in the familiar form of colored kernels on an ear of corn. Students trained on this project will participate in traditional field genetics, chromosome analysis using advanced microscopy, and molecular assays of the genes that control the process of meiosis that divides and segregates chromosomes. Scientists at all levels, ranging from undergraduates at a small liberal arts college to graduate students and postdoctoral fellows at a major research university will participate in this project. One of the most famous exceptions to Mendel's First Law occurs in maize by a chromosome variant known as Abnormal chromosome 10 (Ab10). This chromosome skews segregation in its favor through a mysterious mechanism that involves the formation of "neocentromeres" that move independently during meiosis. Segregation distortion mechanisms such as this are referred to as meiotic drive. Recent data indicate that a novel kinesin gene (Kin618) located on Ab10 controls neocentromeres and meiotic drive in maize. The goal of this work is to fully characterize Kin618 and to initiate a larger study to identify other factors involved. Extensive new sequence resources will be developed to help us interpret the origin and evolution of this fascinating chromosome. These studies will expand our knowledge of the maize genome and provide important new insights into the mechanism of chromosome segregation in plants.This award is co-funded by the Genetic Mechanisms Cluster in the Division of Molecular and Cellular Biosciences and the Plant Genome Research Program in the Division of Integrative Organismal Systems.