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Annabel Morley

Doctor of Philosophy, (Genetics)
Study Completed: 2018
College of Sciences


Thesis Title
Investigating the Evolutionary Changes in Crabtree-negative Yeasts During a Long-term Evolution Experiment

Read article at Massey Research Online: MRO icon

The Crabtree effect is a metabolic strategy that allows yeast to ferment in the presence of oxygen. Not all yeast species display this strategy, and nearly 100 years after its discovery the overall benefit is still unclear. Two key theories attempt to explain this phenomenon: the make-accumulate-consume theory and the rate/yield trade-off theory. Ms Morley investigated whether, in accordance with the rate/yield trade-off theory, Crabtree-negative yeasts evolved a faster growth rate and a lower growth yield when adapting to a high sugar environment. Using an experimental evolution study of 1500 generations, and isolates from six different yeast species, her results demonstrated that growth rate was more likely to increase than decrease while growth yield was more likely to decrease than increase in these yeast populations. Her research illustrated the importance of studying the competitive behaviours of microorganisms in isolation, where selfish traits appear to thrive.

Professor Thomas Pfeiffer
Distinguished Professor Paul Rainey