The Gene Balance Hypothesis: dosage effects in plants.

The concept of genomic balance traces to the early days of genetics. In recent years, studies of gene expression have found parallels to the classical phenotypic studies in that aneuploid changes have greater effects than whole genome changes. This has an explanation in terms of potential stoichiometric imbalances of the gene products encoded in the aneuploid regions. Studies of transcriptional factor mutations indicated that they tend to be haplo-insufficient as heterozygotes. Molecular evolution studies found that genes encoding members of macromolecular complexes were preferentially retained following polyploidy and underrepresented in copy number variants. In this review chapter, we synthesize these observations under the rubric of the Gene Balance Hypothesis.