S2-2.5 Jan. 4 Novelties: interactions between genetics, development and selection. GALIS, F.*; METZ, J.A.J.; Leiden University; Leiden University email@example.com
Evolutionary changes involve changes at the genotypic and phenotypic level. Changes at the genetic level lead to developmental changes at the phenotypic level and these developmental changes lead to changes in the adult phenotype. Selection acts at the level of the phenotype, this determines whether genetic changes can invade populations or not. For a full understanding of evolutionary novelties, one needs to understand the processes that leading to or constraining changes at all organizational levels and the links between the levels. Evolutionary changes of units at different levels are discussed and the complex relationship between changes of different levels. Novelties at all levels consist of A) Changes in the interaction within a unit -> novel function B) Changes in the interaction between units -> novel function A) and B) are often preceded by C) An increase in the number of units. We discuss the importance of factors that constrain evolutionary changes at different levels and that usually prevent them from happening. Particular emphasis will be on duplications and homeotic changes in vertebrates as examples and on developmental and pleiotropic constraints that result from the coordination between patterning and morphogenetic processes during early organogenesis (phylotypic stage). Subsequently we discuss factors that facilitate changes, sometimes relatively drastic ones, again using duplications and homeotic changes as examples. Special emphasis will be on what domestication, as experiments in evolution, can teach us about evolutionary novelties, in particular about the importance of a combination of directional and relaxed selection.