TY - JOUR T1 - Evolution of Gene Expression Balance Among Homeologs of Natural Polyploids JF - G3: Genes|Genomes|Genetics SP - 1225 LP - 1237 DO - 10.1534/g3.116.038711 VL - 7 IS - 4 AU - Mutti, Jasdeep S. AU - Bhullar, Ramanjot K. AU - Gill, Kulvinder S. Y1 - 2017/04/01 UR - http://www.g3journal.org/content/7/4/1225.abstract N2 - Polyploidy is a major evolutionary process in eukaryotes, yet the expression balance of homeologs in natural polyploids is largely unknown. To study this expression balance, the expression patterns of 2180 structurally well-characterized genes of wheat were studied, of which 813 had the expected three copies and 375 had less than three. Copy numbers of the remaining 992 ranged from 4 to 14, including homeologs, orthologs, and paralogs. Of the genes with three structural copies corresponding to homeologs, 55% expressed from all three, 38% from two, and the remaining 7% expressed from only one of the three copies. Homeologs of 76–87% of the genes showed differential expression patterns in different tissues, thus have evolved different gene expression controls, possibly resulting in novel functions. Homeologs of 55% of the genes showed tissue-specific expression, with the largest percentage (14%) in the anthers and the smallest (7%) in the pistils. The highest number (1.72/3) of homeologs/gene expression was in the roots and the lowest (1.03/3) in the anthers. As the expression of homeologs changed with changes in structural copy number, about 30% of the genes showed dosage dependence. Chromosomal location also impacted expression pattern as a significantly higher proportion of genes in the proximal regions showed expression from all three copies compared to that present in the distal regions. ER -