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Universidade de Lisboa (2017)

Dating evolution on island ecosystems : a case-study with the Cape Verde terrestrial biodiversity

Pena, Ana Rita Leal

Titre : Dating evolution on island ecosystems : a case-study with the Cape Verde terrestrial biodiversity

Auteur : Pena, Ana Rita Leal

Université de soutenance : Universidade de Lisboa

Grade : Mestrado em Bioinformática e Biologia Computacional, 2017

Résumé partiel
The interdisciplinary field of bioinformatics was born from the need to develop and employ methodologies to study large amounts of biological data, namely proteins and DNA. Many science areas benefited greatly from the introduction of specialized and powerful tools that improved the implementation of databases, data analysis and biological interpretations. For evolutionary study fields such as phylogenetics, the knowledge jump has been substantial since the introduction of bioinformatic methods in their analysis. Making use of highly advanced software packages is now possible to perform high-throughput DNA sequencing, and thoroughly analyse this data with several methods of phylogenetic inference, to obtain informative and well supported phylogenies. Even though many important evolutionary discoveries were made in the last few years, understanding the evolutionary origin of biological diversity on island ecosystems is still a critical issue within the hotspot area of the Macaronesia Islands (i.e. Azores, Canary Islands, Madeira and Cape Verde). One of the least studies archipelagos is Cape Verde, which houses a huge diversity of endemic species whose evolution is still largely understudied. In these islands, the reptiles are one of the most diverse radiations among the terrestrial groups, hosting three genera with 22 endemic species. Chioninia, a group of skins formerly included in the genus Mabuya ; Hemidactylus, a widespread and diverse group of house geckos ; and Tarentola, a genus of wall geckos that also occurs on other Macaronesia archipelagos. Some of these species are single islands endemics (SIE) and are threatened species, which puts them at high risk of extinction. This study aims to reconstruct a phylogeny for this group with large-scale taxon sampling using a wide sample of the most current bioinformatic tools available. DNA data was retrieved from the Genbank and subsequently analysed using several software packages for alignment, model fitting and finally phylogenetic inference. The collected data was composed of 1725 DNA sequences (1447 coming from Cape Verde) and 15 different genes, which originated from a total of 67 reptilian species. Both approaches – Maximum Likelihood and Bayesian Inference – were used to achieve more thorough results.

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Page publiée le 23 juin 2020