| Popis: |
It is thought that the great majority of the phenotypic disparity present in the animal kingdom was generated in a relatively short time during the Cambrian explosion, around 500 million years ago. Furthermore, it has been suggested that animal body plans have remained largely unchanged since then. In this thesis I describe a series of studies aimed at furthering the understanding ofthe evolution of animal body plans. Chapters 2 and 3 investigate the evolution of segmentation within the animal kingdom. Specifically, Chapters 2 and 3 describe the molecular and functional analyses of the Notch And Delfa homologues of the cockroach, Periplaneta americana. These chapters show for the first time that the Notch pathway is crucial for the development of segments in an insect, a result which, in light of recent work on segmentation in the spider, strongly suggests that Notch-mediated segmentation was ancestral for both insects and arthropods, and lends >. Illlpport to the hypothesis that the segmentation mechanisms in arthropods and chordates may be homologous. Chapters 2 and 3 have been submitted for publication as a research paper in PNAS, in combination with further work that was performed in this system by Juan Pablo Couso and Jose Inyaki Pueyo. |
