Aneuploidy causes tissue-specific qualitative changes in global gene expression patterns in maize.

Segmental aneuploidy refers to the relative excess or deficiency of specific chromosome regions. This condition results in gene dosage imbalance and often causes severe phenotypic alterations in plants and animals. The mechanisms by which gene dosage imbalance affects gene expression and phenotype are not completely clear. The effects of aneuploidy on the transcriptome may depend on the types of cells analyzed and on the developmental stage. We performed global gene expression profiling to determine the effects of segmental aneuploidy on gene expression levels in two different maize (Zea mays) tissues and a detailed analysis of expression of 30 genes affected by aneuploidy in multiple maize tissues. Different maize tissues varied in the frequency at which genes located outside of the aneuploid regions are positively or negatively regulated as well as in the degree of gene dosage compensation. Multiple genes demonstrated qualitative changes in gene expression due to aneuploidy, when the gene became ectopically expressed or completely silenced in aneuploids relative to wild-type plants. Our data strongly suggested that quantitative changes in gene expression at developmental transition points caused by variation in gene copy number progressed through tissue development and resulted in stable qualitative changes in gene expression patterns. Thus, aneuploidy in maize results in alterations of gene expression patterns that differ between tissues and developmental stages of maize seedlings.