About the Project
Use of oxygen is one of the most fundamental prerequisites ofmammalian life. Yet there is remarkable variation in the details of how they deliver it to their tissues - and there are serious gaps in our understanding of this variation. This project aims to address these unanswered questions.
Mammals show a surprisingly high variability in oxygen supply mechanisms, such as differences in blood oxygen affinity, erythrocyte volume and ion regulation, haemoglobin aggregation tendency, retinal and placental vascularization patterns, and adult versus fetal haemoglobin oxygen binding properties. Some of these traits are further linked to genetic polymorphisms and are of great interest to veterinarians and comparative physiologists. Yet their underlying causes have largely remained unexplained.
The aim of this project is to analyze the distribution and trace the evolution of these traits on a time-calibrated mammalian phylogeny to increase our understanding of factors that may have shaped their current physiological diversity. Taking advantage of the recent improvements in our understanding of the evolutionary relationships of mammals and the comparative method in evolutionary biology, a number of possible factors will be assessed that may underpin the observed differences in mammalian blood and tissue oxygen supply mechanism. These factors include changes in atmospheric oxygen levels over the last 250 million years, parent-offspring conflict, evolutionary changes in metabolic rate due to altered activity life styles, scaling effects with body mass, and reduced oxygen availability in high-altitude or subterranean niches. Other traits, like altered erythrocyte ion compositions and haemoglobin aggregation tendency, may have repeatedly evolved for blood parasite defense.
Understanding selection pressures and molecular mechanisms that have shaped the diversity of mammalian oxygen supply mechanisms (from globin genes to mammalian communities) may help identifying predispositions and constraints for adapting to future environmental change, which will directly affect the dynamics of biodiversity
Funding Notes
Competitive funding of tuition fee, research costs and stipend (£14,553 tax-free, 2017-18) from the NERC Doctoral Training Partnership “Adapting to the Challenges of a Changing Environment” (ACCE, http://acce.group.shef.ac.uk/ ). ACCE – a collaboration between the Universities of Sheffield, Liverpool, and York – is the only dedicated ecology/evolution/conservation Doctoral Training Partnership in the UK.
Applications (CV, letter of application, 2 referees) by email to [Email Address Removed], deadline: January 9th 2018. Interviews: 14th-16th February 2018. Shortlisted applicants will be interviewed for only one project from the ACCE partnership.
This project is also available to self-funded students. A fees bursary may be available
References
Mirceta, M., Signore, A. V., Burns, J. M., Cossins, A.R., Campbell, K. L., and Berenbrink, M. (2013). Evolution of mammalian diving capacity traced by myoglobin net surface charge. Science340, 1234192.
Opazo, J. C., Hoffmann, F. G., Natarajan, C. , Witt, C. C., Berenbrink, M ., and Storz, J. F. (2015). Gene turnover in the avian globin gene families and evolutionary changes in hemoglobin isoform expression. Molecular Biology and Evolution32: 871-887.
Koldkjaer, P., McDonald, M. D., Prior, I., and Berenbrink, M. (2013). Pronounced in vivo hemoglobin polymerization in red blood cells of Gulf toadfish. A general role for hemoglobin aggregation in vertebrate hemoparasite defence?. American Journal of Physiology305, R1190-R1199.
Arbuckle, K., Bennett, C. M. and Speed, M. P. (2014). A simple measure of the strength of convergent evolution. Methods in Ecology and Evolution5, 685–693.
Continue with Facebook
