Analyzing developmental sequences within a phylogenetic framework.

摘要: Heterochronyisimportantasapotentialmechanism ofevolutionarychange.However,the analysis of developmental timing data within a phylogenetic framework to identify important shifts has proven difecult. In particular, analytical problems with sequence (event) heterochrony revolve around the lack an absolute time frame in development allow standardization across species. An breakthrough this regard is method "event-pairing," which compares relative events pairwise fashion. The resulting event-pair-encoded can be mapped onto phylogeny, provide biological information. However, event-paired are cumbersome work and rigorous quan- titative under analyze them. Critically, otherwise advantageous relativity event-pairing prevents assessment whether one or both single event-pair have changed position during evolutionaryhistory. Building on ofevent-pairing, we describea protocolwherebyevent-pairtransformationsalongagivenbranchareanalyzedenbloc.Ourmethodof "event-pair cracking"thereby allowsdevelopmentaltiming datatobeanalyzed quantitatively infer key heterochronic shifts. We demonstrate utility cracking through worked example show how it provides set desired features identieed by previous authors. (Character mapping; development; event-pairing; evolutionary transformations; heterochrony; framework.)