1. Divergent gene expression levels between diploid and autotetraploid Tolmiea relative to the total transcriptome, the cell, and biomass.
- Author
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Visger CJ, Wong GK, Zhang Y, Soltis PS, and Soltis DE
- Subjects
- Biomass, Cell Size, Saxifragaceae metabolism, Transcriptome, Diploidy, Gene Expression, Saxifragaceae genetics, Tetraploidy
- Abstract
Premise of the Study: Studies of gene expression and polyploidy are typically restricted to characterizing differences in transcript concentration. Using diploid and autotetraploid Tolmiea, we present an integrated approach for cross-ploidy comparisons that account for differences in transcriptome size and cell density and make multiple comparisons of transcript abundance., Methods: We use RNA spike-in standards in concert with cell size and density to identify and correct for differences in transcriptome size and compare levels of gene expression across multiple scales: per transcriptome, per cell, and per biomass., Key Results: In total, ~17% of all loci were identified as differentially expressed (DEGs) between the diploid and autopolyploid species. The per-transcriptome normalization, the method researchers typically use, captured the fewest DEGs (58% of total DEGs) and failed to detect any DEGs not found by the alternative normalizations. When transcript abundance was normalized per biomass and per cell, ~66% and ~82% of the total DEGs were recovered, respectively. The discrepancy between per-transcriptome and per-cell recovery of DEGs occurs because per-transcriptome normalizations are concentration-based and therefore blind to differences in transcriptome size., Conclusions: While each normalization enables valid comparisons at biologically relevant scales, a holistic comparison of multiple normalizations provides additional explanatory power not available from any single approach. Notably, autotetraploid loci tend to conserve diploid-like transcript abundance per biomass through increased gene expression per cell, and these loci are enriched for photosynthesis-related functions., (© 2019 Botanical Society of America.)
- Published
- 2019
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