Allelic variation in gene expression in Populus F₁ hybrids

• Main Author: Zhuang, Yan
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/32284

Plant hybridization can induce phenotypic novelty and speciation as well as genome rearrangements and gene expression changes. Populus hybrids provide a good system to study interspecific hybridization and its genetic and molecular consequences. In this project I determined the allelic variation of gene expression in Populus trichocarpa x Populus deltoides F₁ hybrids using a single-base primer extension assay. Among 30 genes analyzed in four independently formed hybrids, 17 showed above 1.5 fold expression biases for the two alleles, and the expression patterns differed between leaves and stems for 9 genes. These results suggest differential regulation of the two parental alleles in the Populus F₁ hybrids. To determine if the allelic expression biases were caused by hybridization I compared the ratios of species-specific transcripts between a hybrid and clones of its parents. Modes of gene regulation were inferred from the hybrid-parent comparisons. C«-regulation was inferred for 6 out of 19 genes. The remaining 13 genes including 1 controlled by trans-regulation and 12 by combined cis- & trans-regulation showed allelic expression ratios in the hybrid that were significantly different from the parental ratios, suggesting an alteration of the regulation network induced by hybridization. === Land and Food Systems, Faculty of === Graduate