cellular mechanisms by which different organisms grow and develop is fundamental for understanding the evolution of the diversity of animal forms seen on the planet today. It is unclear, however, how changes in gene expression during ontogeny result in the diversity of animal body plans seen in the planet today. This project will thus aim to link genotype to phenotype to understand the role of gene expression and ontogeny in the evolution of biomineralized skeletons. Sea urchins are a model system for understanding the evolution of skeletal morphology because the genetic regulatory networks that build their larval and embryonic skeletons are well known. Furthermore, they have a well-sampled fossil record, which makes them an ideal model system to understand evolutionary changes in morphology seen in deep time. The aim of this project is to quantify morphological changes in skeletal morphology during ontogeny of the sea urchin Mespilia globulus, and then identify the molecular mechanisms underlying skeletal growth. The student will then compare morphology at different developmental stages to the fossil record of echinoderms to test the hypothesis that morphological differences in the skeleton of different echinoderm groups is underlain by changes in ontogeny.
The student will carry out groundbreaking work with a new model animal system for understanding the evolution of biomineralization and skeletal development, the sea urchin Mespilia globulus. The proposed research will use a molecular palaeobiological approach, combining data from development and gene expression with the fossil record. Dependent upon the interest of the student, you can:
- Use micro-CT scanning to build a morphology-based staging scheme for post-metamorphic development in M. globulus and use geometric morphometrics and calculation of skeletal density to quantify changes in skeletal growth through development. This will identify the changes in biomineral growth that underlie changes in morphology.
- Use assays of gene expression and protein localization, predominantly HCR RNA-FISH and immunohistochemistry to identify components of the biomineralization toolkit which underlies skeletal growth in this species and pair changes in spatial gene expression with changes in morphology. This will identify the molecular basis for skeletal development in this animal.
- You will then have the opportunity to compare the staging scheme with morphological and morphometric data from the fossil record of echinoderms to statistically identify the role of ontogenetic and developmental changes in the evolution of their body plans.
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. Specific training will include:
Generation and analysis of micro-CT scan data
Analysis of 3D geometric morphometric data
Embryological techniques such as spawning and culturing sea urchins
Generation and analyses of gene expression data using Hybridisation chain reaction RNA Flourescent in situ hybridization
Generation and analyses of protein localization using in situ hybridization and immunohistochemistry
Analysis of fossil specimens from museum collections
Statistical analyses using R
Please see https://inspire-dtp.ac.uk/how-apply for details.
Thompson, J.R., Paganos, P., Benvenuto, G., Arnone, M.I. and Oliveri, P., 2021. Post-metamorphic skeletal growth in the sea urchin Paracentrotus lividus and implications for body plan evolution. EvoDevo, 12(1), pp.1-14.
Gao, F., Thompson, J.R., Petsios, E., Erkenbrack, E., Moats, R.A., Bottjer, D.J. and Davidson, E.H., 2015. Juvenile skeletogenesis in anciently diverged sea urchin clades. Developmental biology, 400(1), pp.148-158.
