The nature of standing genetic variation

This is a recently funded project in which we plan to investigate the relationships between pre-existing (standing) genetic and new mutational variance. Working with Drosophila serrata, we plan to characterise the effects of new mutations on body size, and see how this distribution depends on the ancestral body size and/or fitness. Please get in touch if you are interested in being involved with this project.

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Understanding rapid adaptation to new environments

The roles of phenotypic plasticity and trait mean evolution in responses to rapid environmental change are difficult to disentangle. Using manipulative experiments in both our study systems, we aim to better understand how genetic variation for quantitative phenotypes varies with environment.

In the biomedical model organism, zebrafish, Danio rerio, we plan to induce new genetic variation through mutagenesis, and to characterise mutational variation in swimming performance across different temperatures. Combining breeding design and analyses with artificial selection, we aim to determine the effects of mutation on performance at specific temperatures, on plasticity (i.e. the change in speed with temperature), and on the covariances across temperature, and between plasticity and average performance. In particular, we aim to determine whether variance is greater at novel temperatures, and how much variation in performance at a temperature is shared across temperature.

We are also investigating the commonality of effects of different environmental stressors, and the interaction of multiple stressors, on mutational variance. Using Drosophila serrata, we are collaborating with Professor Carla Sgro (Monash University) to determine how mutational variance varies with temperature and nutrition.

The contribution of mutation to phenotypic variation in outbred populations

We aim to characterise the effect of new mutations, arising each generation, in an outbred, randomly mating population. We have collected data on wing shape of male Drosophila serrata from 600 families each generation, over 14 generations in a pedigreed population. We also have genotypes of the sires of these families each generation. One aim of this project is to determine whether estimates of mutational variance and covariance from inbred lines experimental designs adequately characterise the true effects in natural populations.

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Morphology – performance maps

An ongoing and overarching goal of much of our zebrafish work is to understand more about the genetic basis of the relationship between body shape and swimming speed in fish, and how this relationship varies, including variation between the sexes, due to changes in genetic variation (mutation), due to swimming temperature, and in response to indirect selection on performance.