Research Objectives: Partial chromosome duplications (segmental duplications) are important contributors to the structure, function and diversity of plant and animal genomes. However, very little is known concerning how duplications are generated, and their immediate effects on gene expression and genetic recombination. This project examines the potential role of transposable elements, or jumping genes, in generating segmental duplications. The aim of this project is to isolate and characterize a series of partial chromosome duplications in corn generated by Ac/Ds transposable elements. The structures of duplications will be examined by microscopic visualization of chromosomes. The duplication endpoints will be isolated and studied to determine precisely how DNA replication and genetic recombination are involved in forming duplications. Finally, the effects of partial chromosome duplications on genetic recombination and gene expression will be analyzed in detail, because these two processes are critical for effective plant breeding. This project utilizes complementary molecular, genetic and microscopic approaches to study this important class of genetic variants.
Broader Impacts: This project will provide significant new insight into the role of transposable elements in generating duplications, and the impact these duplications have on genetic recombination and gene expression. This information may lead to significant advances in breeding of crop plants, thereby improving agricultural efficiency and environmental sustainability. In addition, this project will result in significant training opportunities for current and future scientists in a variety of approaches and methods in molecular genetics, classical genetics, cytogenetics and transposon biology. Three graduate students are integral to the research project and will be trained in a variety of classical, cytological, and molecular genetic approaches. The project will also provide laboratory work experience and on the job training for approximately six undergraduate students per year. In addition, an annual cytogenetics short course will train 12-18 high school students and teachers yearly. Together these training activities will significantly enhance the science infrastructure in the USA.
Partial chromosome duplications (segmental duplications) are important contributors to the diversity of natural genes and genomes. However, very little is known concerning how duplications are generated, and their immediate effects on gene expression and recombination. This project examined the potential role of transposable elements, or jumping genes, in generating segmental duplications. One aim of this project was to isolate and characterize a series of partial chromosome duplications in corn generated by Ac/Ds transposable elements. A series of duplications were successfully isolated and examined by microscopic visualization of chromosomes. The duplication endpoints were isolated and studied to determine precisely how DNA replication and genetic recombination are involved in forming duplications. Finally, the effects of partial chromosome duplications on genetic recombination and gene expression were analyzed in detail, because these two processes are critical for effective plant breeding. This project utilized complementary molecular, genetic and microscopic approaches to study this important class of genetic variants. Overall, this project provided significant new insight into the role of transposable elements in generating duplications, and the impact these duplications have on genetic recombination and gene expression. This information may lead to significant advances in breeding of crop plants, thereby improving agricultural efficiency and environmental sustainability. The results of this project were presented in a number of peer-reviewed publications in leading scientific journals. In addition, a series of animated models of the mechanisms of transposition-induced genome rearrangements were prepared and made available to the public at the website http://jzhang.public.iastate.edu/Transposition.html The animated models show how various transposition pathways can lead to genome rearrangements. The animations are available for download, and scientists and educators worldwide have stated that these animations are very helpful for teaching the concepts of transposition-induced genome rearrangements. In addition, this project resulted in significant training opportunities for current and future scientists in a variety of approaches and methods in molecular genetics, classical genetics, cytogenetics and transposon biology. Three graduate students were trained in classical, cytogenetic, and molecular genetic approaches. The project also provided laboratory work experience and on the job training for approximately six undergraduate students per year. In addition, an annual cytogenetics short course was provided for approximately 12 high school students yearly. These educational activities provide training and experience that is otherwise unavailable to young students and future scientists, and will thereby help to enhance the potential for scientific and technological research in the USA.
