Filogenia molecular de Tunicata com ênfase em Ascidiacea

• Ano de defesa: 2006
• Autor(a) principal: Lopes, Daniele Pequeno
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Cordados; Filogenia; Molecular; Recursos pesqueiros e engenharia de pesca; Urocordados
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/1127

Phylogenetic relationships among many animal groups have been considered unclear by zoologists for many years, as morphological markers sometimes led to unsatisfactory results. The development of molecular techniques allowed the understanding of evolutionary relationships of many taxa, questioning previous phylogenetic recosntructions based on physiological and morphological aspects, fossil records, and other sources of data. As a result, there was a great development of scientific production regarding phylogenetic studies of distinct groups, including Tunicata and Ascidiacea. Despite the many works proposing hypothesis about relationships between those taxa, there are many conflicting data. The aim of the present work is to review the phylogeny of Tunicata, focusing on the taxon Ascidiacea, by analyzing the 18S nrDNA region of Microcosmus exasperatus, which was obtained through extraction based on CTAB reagent, along wiht other species whose sequences were available on GenBank. In order to achieve the desired target sequence, PCR reactions using universal primers that matched that region were performed and the consensus sequence obtained was compared to other sequences to produce phylogenetic trees. Tha analysis of the cladograms obtained indicated that Chordata and its subphyla are indeed monophyletic. Regarding the Tunicata, Appendicularia was identified as the most basal group. It was not possible to confirm the division of Ascidiacea into two distinct orders: Pleurogona and Enterogona. However, Phlebobranchia, Aplousobranchia and Stolidobranchia were present in most of the trees. Appendiculariaa was considered monophyletic, and Ascidiacea and Thaliacea were identified as paraphyletic groups, where the latter presented a close relationship with phlebobranch ascidians. Stolidobranchia appeared as a monophyletic group in most of the cladograms, showing Molgulidae also as monophyletic in a basal position. Phlebobranchia is also monophyletic and included the family Cionidae as one of its representatives.