Global Expression Change Accompanying Polyploidy
Polyploidy appears at a high frequency in the plant tree of life, but the mechanics of how two divergent genomes reunite (allopolyploidy) has many unanswered questions. Similarly, an understanding of the adaptive advantage remains vague. To better understand the mechanistic changes accompanying gene expression following polyploidy, we examined the global expression state of the cotton genome (roughly 40,000 unique genes interrogated by 7 probes each) in both the parents and the synthetically doubled F1 generated from their cross. We conducted this experiment in two separate backgrounds, each time G. arboreum (Africa, A Genome) was the maternal donor and was crossed to G. thurberi (Mexico, D Genome) and G. bickii (Australia, G Genome). The diagram below illustrates these species.
We grew three sets of 30 plants (5 per species) in separate growth chambers to control for environmental variation and extracted RNA from leaf tissue. We then pooled RNA from three individuals and hybridized three technical replicates per chamber per species, producing the following results:
We see many novel things going on in the allopolyploid, including a strong signal of genomic dominance. We are currently completing the manuscript for his work.