ABSTRACT
Understanding the role of ancient whole genome duplications (WGD) in generating the complexity of life on earth is an important goal of comparative genomics. Recent genomic analyses have found that most angiosperm lineages have had one to several rounds of WGD in their history (Soltis et al. 2009), including two WGDs unique to the order Brassicales. It has been suggested that WGDs have contributed to evolutionary innovations and success across all eukaryotes (Freeling and Thomas 2006). Specifi cally, genes whose products function in highly-connected portions of signaling or regulatory networks (i.e., highly-pleiotropic) are signifi cantly over-retained following WGDs and are not duplicated via non-WGDs to maintain proper balanced gene expression (e.g., the Gene Balance Hypothesis: Birchler and Veitia 2007; Freeling 2008, 2009; Edger and Pires 2009; Veitia et al. 2008).
