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Grantee Research Project Results

Grantee Research Project Results

The Genetic Basis of Plant Morphological Variation: A Molecular and Genetic Examination of Maize and its Relatives

EPA Grant Number: U915211
Title: The Genetic Basis of Plant Morphological Variation: A Molecular and Genetic Examination of Maize and its Relatives
Investigators: Lukens, Lewis N.
Institution: University of Minnesota - Twin Cities
EPA Project Officer: Boddie, Georgette
Project Period: September 1, 1997 through September 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Fellowship - Molecular Biology/Genetics , Academic Fellowships , Biology/Life Sciences

Description:

Objective:

The domestication of grasses occurred independently in several different geographic areas, yielding such modern crops as rice, maize, wheat, and sorghum. These domestication events often resulted in the acquisition of common morphological characters such as enhanced stature and increased floret number. The objectives of this research project are to: (1) understand the genetic and molecular bases for these morphological changes, and I am using domesticated maize (Zea mays spp. mays) and its wild ancestor, teosinte (Zea mays spp. parviglumis), as a model system to investigate these changes; and (2) examine whether the same genes involved in the domestication of maize also contributed to the morphological variation found in wild species. The domestication of grasses occurred independently in several different geographic areas, yielding such modern crops as rice, maize, wheat, and sorghum. These domestication events often resulted in the acquisition of common morphological characters likesuch as enhanced stature and increased floret number. A major goal of my research is to understand the genetic and molecular bases for these morphological changes, and I am using domesticated maize (Zea mays spp. mays) and its wild ancestor, teosinte (Zea mays spp. parviglumis), as a model system to investigate these changes. I am also examining whether the same genes involved in the domestication of maize also contributed to the morphological variation found in wild species.

Approach:

Previous work has identified five quantitative trait loci QTL (quantitative trait loci QTL), which contribute to the morphological evolution of maize. To test for epistasis and allele-specific environmental responses among QTL involved in maize evolution, two QTL, which account for much of the morphological variation in a maize x teosinte F2 population were introgressed into an isogenic maize background. The four homozygous classes for the two QTL were grown in two environments, and three morphological traits and the level of mRNA accumulation for one QTL were measured. To determine the pattern of nucleotide change within the gene allelic to one QTL, tb1, and to test whether the gene or a certain domain of the gene has evolved under positive selection in wild species, tb1 sequences were cloned from diverse taxa and analyzed using molecular evolutionary analyses.

Supplemental Keywords:

fellowship, plant morphological variation, maize, domestication, morphological evolution, quantitative trait loci, QTL.

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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