Research Interests

I have spent most of my career studying transposition and recombination, two main contributors to genetic variability in plants. Maize species diversity is manifested at all levels, ranging from plant shape to chromosomal structure. My lab recently discovered that the sequence of the same region of the genome can vary by as much as 70% between unrelated individuals. This unprecedented intraspecific variation in genome structure arises from differences in the content of intergenic transposable DNA elements (transposons), some of which most likely influence expression of the adjacent genes. Complementary variation in gene expression between unrelated lines may underlie the vigor seen in their hybrid progeny. The process of meiotic recombination shuffles chromosomal segments that otherwise would be inherited together. We found that recombination in maize is restricted to genes, which comprise a small fraction of the genome, and does not take place in the highly repetitive transposons. This pattern of recombination probably evolved as a mechanism to protect the genome from self-destruction at meiosis, when recombination is required for proper chromosomal disjunction. A few transposons are very active in maize. My lab studies their architecture and interactions, uses them as tools to elucidate gene function, and is engineering them to create a more efficient reverse genetics resource for the community.

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Primary Section

Section 62: Plant, Soil, and Microbial Sciences