A survey of ancient paralog expression patterns in Arabidopsis thaliana root cell-types

Whole-genome duplication events have played an extensive role in the evolution of flowering plants. The sudden doubling of genetic material can expedite large scale changes in gene function and expression patterns. This process can be an adaptively beneficial source of genetic variation.

In the context of paleopolyploids, wherein there are identifiable remnants of an ancestral polyploidy event in a diploid species, this often facilitates the diversification of gene families as these duplicated genes are no longer selectively constrained to one specific function or regulatory pattern. Alternative splicing (AS) offers an avenue with which genes duplicated by these polyploidy events may further contribute to the functional complexity of the cell.

While the extent to which AS influences functional or regulatory divergence in ancient paralogs has been previously investigated, such as those derived from the α-WGD event in Arabidopsis thaliana, the manifestation of this divergence in distinct tissues and cell-types is less understood. Using RNA-Seq data I have surveyed the transcriptomes of root developmental zones and their constituent cell-types in paleopolyploid Arabidopsis thaliana. Incorporating such high-resolution data with further in silico analyses, this demonstrates near-complete divergence in both gene expression and splicing patterns.