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Title: MAIZE INDIVIDUALIZED CHROMOSOME AND DERIVED RADIATION HYBRID LINES AND THEIR USE IN FUNCTIONAL GENOMICS

Author
item KYNAST, R - UNIVERSITY OF MINNESOTA
item OKAGAKI, R - UNIVERSITY OF MINNESOTA
item RINES, HOWARD
item PHILLIPS, R - UNIVERSITY OF MINNESOTA

Submitted to: Functional and Integrative Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2002
Publication Date: 4/9/2002
Citation: KYNAST, R.G., OKAGAKI, R.J., RINES, H.W., PHILLIPS, R.L. MAIZE INDIVIDUALIZED CHROMOSOME AND DERIVED RADIATION HYBRID LINES AND THEIR USE IN FUNCTIONAL GENOMICS. FUNCTIONAL AND INTEGRATIVE GENOMICS. 2002. V. 2. P. 60-69.

Interpretive Summary: The identification and assignment of function to the thousands of genes comprising the genome (the complete genetic material) of a species like corn with a large, complex genome is a formidable task. The DNA comprising the genome of plants and animals comes distributed in packages termed chromosomes. The basic number of chromosomes varies with species; corn has ten. Earlier we described the recovery of some novel partial hybrids between corn and another cereal, oat, in which a portion of the corn's genetic material, one of the ten chromosomes, is added to the complete genome of oat. The recovered plant is basically an oat plant carrying a specific portion of the corn genome. Furthermore, by exposing such plants to gamma irradiation to break up the chromosomes, we recovered plants with just a segment of a corn chromosome in an oat genetic background. By isolating a piece of a corn chromosome in an alien genetic background, we can analyze what corn genes are present on it. Also, we sometimes gain information about the function of corn genes that are located on this segment of corn chromosome by its effect on the oat plant hosting it such as modified plant shape, flowering time, or seed composition. These oat plants with corn chromosomes or chromosome segments added to their genomes provide valuable tools for the many scientists analyzing the structural and functional components the corn genome. Information gained from studies of these chromosomes and chromosome segments will be useful in identifying and isolating specific genes involved in crop quality and development. This information will give corn breeders new targets for developing improved corn and other grain crops.

Technical Abstract: The duplicated and rearranged nature of plant genomes frequently complicates identification, chromosomal assignment and eventual manipulation of DNA segments. Separating an individual chromosome from its native complement by adding it to an alien genetic background together with the generation of radiation hybrids from such an addition line can enable or simplify structural and functional analyses of complex duplicated genomes. We have established fertile disomic addition lines in oat for each of the individual maize chromosomes, except chromosome 10. We report on instability and transmission in disomic additions of maize chromosomes 1, 5, and 8; the chromosome 2, 3, 4, 6, 7, and 9 additions appear stable. The photoperiodic response of maize chromosome 1 addition lines is presented with regard to seed set and maize chromosome transmission. Low resolution radiation hybrid maps are presented for maize chromosome 2 and 9 to illustrate their potential for rapid physical mapping of large numbers of DNA sequences, such as ESTs. The potential of addition and radiation hybrid lines for mapping duplicated sequences or gene families to chromosome segments is presented and also the use of the lines to test interactions between genes located on different maize chromosomes as observed for ectopic expression of cell fate alterations.