Genomic and epigenomic bases of transgressive segregation - New breeding paradigm for novel plant phenotypes.

For a holistic approach in developing the stress-resilient crops of the 21 century, modern genomic biology will need to re-envision the underappreciated phenomena in classical genetics, and incorporate them into the new plant breeding paradigm. Advances in evolutionary genomics support a theory that genetic recombination under genome shock during hybridization of widely divergent parents is an important driver of adaptive speciation, by virtue of the novelties of rare hybrids and recombinants. The enormous potential of genetic network rewiring to generate developmental or physiological novelties with adaptive advantage to special ecological niches has been appreciated. Developmental and physiological reconfiguration through network rewiring involves intricate molecular synergies controlled both at the genetic and epigenetic levels, as typified by the phenomenon of transgressive segregation, observed in both natural and breeding populations. This paper presents modern views on the possible molecular underpinnings of transgressive phenotypes as they are created in plant breeding, expanded from classical explanations through the Omnigenic Theory for quantitative traits and modern paradigms of epigenetics. Perspectives on how genomic biology can fully exploit this phenomenon to create novel phenotypes beyond what could be achieved through the more reductionist approach of functional genomics are presented in context of genomic modeling.