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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities
 

Lead Supervisor: Robert Asher, Zoology

Co-Supervisor: Daniel Field, Earth Sciences

Brief summary: 
This project seeks to assess the information content of fossilizable data, reconstruct the morphology of fossil ancestors as predicted by genomic data, and provide a genomically informed means with which to assess the evolutionary affinities of long-extinct species.
Importance of the area of research concerned: 
This project focuses on the interrelationships and morphology of living and fossil vertebrates. Many branches on life's evolutionary tree were well-established by the close of the 19th century; others have been resolved more recently, and yet others remain contentious. Resolving the tree of life is important both in applied and theoretical biology, e.g., in interpreting animal models and testing hypotheses of character acquisition (respectively). Data relevant for phylogenetics come from many sources, including development, adult phenotype, and genetics. Patterns of growth (e.g., dental eruption and in formation of the axial skeleton), have also proven to be informative. Only a subset of these data sources are typically available for fossils, yet most species that have ever existed during the course of Earth History are now extinct. Methods to accurately reconstruct phylogeny, including fossils, and assess our confidence in it are therefore of key importance to understanding past Life on Earth.
Project summary : 
We seek to understand vertebrate evolution by applying methods in comparative anatomy, development, and phylogenetics . By applying palaeontological datasets to test phylogenetic questions for species with well-corroborated positions on the Tree of Life, we can gauge the accuracy of a palaeontological dataset relative to soft-tissues and DNA. We will also extract character data from vertebrate species using histology and microCT, combining with DNA where feasible. These techniques not only greatly augment the information content of a given sample, but also provide novel data on patterns of growth and intraspecific variation when relevant samples are accessible.
What will the student do?: 
The student will formulate and test hypotheses on vertebrate evolution by collecting comparative anatomical data on living and fossil species using collections-based research, microCT, and/or histology. Using well-corroborated branches on the tree of life (e.g., living placental mammals), the student will undertake heuristic tests of phylogenetic accuracy among fossils based on subsets of osteology, soft tissues and DNA. Where available, the student will also collect data on developmental changes to phenotype during the course of growth. The student will analyze these data to quantify accuracy of paleontological phylogenetic hypotheses and test generalizations of of systemic bias in paleontological phylogenetics.
References - references should provide further reading about the project: 
Asher RJ, Smith MR. 2021. Phylogenetic Signal and Bias in Paleontology. Systematic Biology. https://doi.org/10.1093/sysbio/syab072
Asher RJ, Smith MR, Rankin AH, Emry, RJ. 2019. Congruence, fossils, and the evolutionary tree of rodents and lagomorphs. Royal Society Open Science 6: 190387. https://doi.org/10.1098/rsos.190387
Pattinson DJ, Thompson RS, Piotrowski A, Asher RJ. 2015. Phylogeny, paleontology, and primates: do incomplete fossils bias the tree of life? Systematic Biology 64(2):169-186. https://doi.org/10.1093/sysbio/syu077
Applying
You can find out about applying for this project on the Department of Zoology page.
Dr Daniel Field
Dr Robert Asher
Department of Zoology Graduate Administrator