Dosage effects on gene expression in a maize ploidy series

Abstract

Previous studies on gene expression in aneuploids revealed numerous trancacting dosage effects. Segmental aneuploidy of each varied chromosomal region exhibited predominantly inverse effects on several target genes. Here, dosage regulation was examined in a maize (&a mays L.) ploidy series where the complete genomic complement is vaned. Total RNA from leaf tissue of monoploid, diploid, triploid, and tetraploid plants ( l x , 2X, 3X, and 4X, respectively) was analyzed for the expression of 18 genes. For most tested genes, the transcript level per cell is directly proportional to structural gene dosage; that is, on a per genome basis, there is approximately equal expression among the four ploidies. Exceptional cases show a negative correlation of expression with ploidy or a positive correlation greater than expected from the structural gene dosage. These studies suggest that, in general, as structural gene dosage increases in multiples of the monoploid complement, the absolute level of gene expression per cell increases. In contrast, addition or subtraction of only a single chromosome arm tends to alter gene expression patterns extensively. The combined results of the euploid and aneuploid studies suggest that aneuploid effects result from an altered stoichiometry of the factors contributing to the mechanisms of gene expression.

Polyploid clades tend to be more speciose than their putative sister clades

“…Direct, simple changes in traits like body size are rare 107 , as in most cases developmental mechanisms regulate, eliminate or modify these effects 108 . Instead polyploidy often affects gene expression in complex ways to produce a broad range of 'hybrid vigour' effects 109 , including downregulation as well as the upregulation of genes 110 . While polyploidy can introduce errors into cell division that increase the likelihood of sterility 111 and other deleterious consequences 112,113 , certain groups (e.g.…”

Allele-specific expression variation at different ploidy levels in Squalius alburnoides

“…In any case, such differences between homoeologs may result in differential transcription rates and/or differential transcript decay between transcripts derived from each homoeolog, a phenomenon called homoeolog expression bias (HEB) 7,8 . Studies on allopolyploids that have analyzed HEB are numerous for plants and go back several years 9–15 . However, the same phenomenon was only much later described in a vertebrate organism 16,17 , the allopolyploid teleost fish S. alburnoides complex.…”