El día 13 de agosto a las 15hs en el Auditorio del CenPat, Jack W. Sites Jr., del Departamento de Biology and Monte L.Beam Museum, Birgham Young University, Provo (Utah, EEUU), dio una conferencia titulada FULFILLING DARWIN’S DREAM: PROGRESS ON THE SQUAMATE TREE OF LIFE |
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| In the original (1859) edition of “The Origin”, Charles Darwin hypothesized that all living species were interconnected through a series of shared ancestors in one great “Tree of Life”. Evidence from multiple disciplines has confirmed the truth of this statement, but reconstructing this “Tree of Life” poses a fomidable challenge, due in part to both the sheer number of living species and distinct populations (the smallest branches on the tree), and the length of time into the distant past that connects all living and extinct species to our common ancestor. A beginning to this problem can be made by reconstructing relationships among clades along modestsized branches, and then eventually linking these to their larger branches, and so on. One branch receiving detailed study is the clade Squamata, the “scaly reptiles” (lizards, snakes, & amphisbaenians). With more than 8,000 species, squamates are the second largest group of vertebrates after birds, and many critical questions in their evolution remain unresolved, such as identification of the most primitive clade of squamates, the origin of the strange amphisbaenians, the origin of snakes, and the relationships of venomous snakes to other snake lineages. An international team of eight investigators from six institutions is collaborating to resolve squamate relationships, using anatomical data from living and fossil forms, in combination with DNA sequences from 50 nuclear genes, for 153 living species – chosen to represent all recognized families and subfamilies of the group. Anatomical data are obtained using traditional methods and high resolution X-ray scanning techniques, and sequence data are generated by incorporating new tools and databases from recent vertebrate genome projects. This seminar will present a “progress report” on this effort, based on some of the data collected to date. | |
