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Visar resultat 1 - 5 av 7 avhandlingar som matchar ovanstående sökkriterier.
1. Evolution of the G protein-coupled receptor signaling system : Genomic and phylogenetic analyses
Sammanfattning : Signal transduction pathways mediated by G protein-coupled receptors (GPCRs) and their intracellular coupling partners, the heterotrimeric G proteins, are crucial for several physiological functions in eukaryotes, including humans. This thesis describes a broad genomic survey and extensive comparative phylogenetic analysis of GPCR and G protein families from a wide selection of eukaryotes. LÄS MER
2. The Dawn of a New Age : Interrelationships of Acoela and Nemertodermatida and the Early Evolution of Bilateria
Sammanfattning : Deciphering the rapid emergence of bilaterian animals around the time of the Cambrian Explosion and reconstructing the interrelationships of animal groups have long been two of the most elusive problems in Zoology. This thesis concerns the phylogenetic interrelationships within and among Acoela and Nemertodermatida, two groups of small worms that are believed to be basal bilaterians and which may provide important clues for understanding the early evolution of animals. LÄS MER
3. Origin and Lifestyles of early Brachiopods and other Lophotrochozoans : Insights from the Chengjiang and Guanshan Fossil-Lagerstätten
Sammanfattning : One of the great unsolved evolutionary questions concerns the origin and phylogeny of the major animal phyla that appeared in the fossil record more than 540 million years ago, during the Cambrian explosion. Although new molecular information has been very useful, we still have little understanding about the origin of most of the phyla of bilaterians living today. LÄS MER
4. Exceptionally Preserved Cambrian Lophotrochozoa : Taxonomy, Systematics and Taphonomy of Chengjiang and Indian Springs Lophophorates
Sammanfattning : The origin and evolution of Lophotrochozoa can be traced to the plethora of lower Cambrian scleritome taxa. We aim to determine the character suites linking these stem-Lophotrochozoa to their extant crown relatives, in particular the small shelly tommotiids and the stem-group brachiopods. LÄS MER
5. Early Cambrian Problematic Lophotrochozoans and Dilemmas of Scleritome Reconstructions
Sammanfattning : The emergence and radiation of metazoan body plans around the Precambrian/Cambrian boundary, some 500-600 million years ago, seems to be concordant with the appearance and diversification of preservable hard parts. Several Precambrian soft-bodied, multicellular organisms most likely represent stem-group bilaterians, but their fossil record is rather sparse. LÄS MER
