The project will develop a method to visually identify each of the ten chromosomes of maize. A set of probes that localize to specific sites on each chromosome and that produce a specific pattern of fluorescence will be generated. Once this method is optimized, the variation of karyotypes (chromosome images) among diverse maize germplasm and closely related species will be determined. The types of organelle genome transfer to the nucleus in these materials will be established. The karyotyping system will be used to examine the nature of genome size variation in hybrid plants by determination of changes in quantity of repetitive sequence arrays at different locations in the genome. Primed in situ labeling coupled with polymerase chain reaction amplification will be adapted for maize chromosomes and used to test the ability to detect specific subclasses of repeated sequences as well as the visualization of individual genes and introduced genes. Chromosome painting probes will be developed from diverse sources and used to label the chromosomes with multiple colors as an aid to detection of subtle changes in chromosome structure.
The development of a robust chromosome identification system will enhance studies of maize genomics. With the ability to identify each chromosome, determinations of changes in chromosome number and structure can be easily made. Investigations that examine chromosome behavior or rearrangement will be greatly facilitated. Variations in gene structure in different lines of maize can be visualized using primed in situ polymerase chain reaction amplification. The completion of this project will reveal new knowledge about chromosome structure, organelle genome transfer, the behavior and variation of repetitive sequences and the evolution of the genome.
Access to project outcomes The results will be presented in publications and a project website that will be linked to the MaizeGDB database.
