Periodic Reporting for period 1 - URBANEPIGENETICS (The epigenetic basis of early-life effects in a wild bird exposed to urban environmental stress)
Reporting period: 2015-04-01 to 2017-03-31
There is increasing evidence that exposure to “stressors”, such as air pollutants, causes changes in the structure of DNA. Specifically, stress-exposure can change the number and location of methyl groups that are attached to DNA, which can subsequently affect gene expression. In other words, environmental conditions can determine which genes are switched on or off and the level at which they are expressed. Patterns of gene expression subsequently influence the establishment of characteristics or traits, for example body size and immune responses. Thus, DNA methylation may mechanistically link environmental conditions and observable characteristics of an individual.
In particular, the environment experienced during early life is known to be very important, in both humans and animals, for determining fixed life-long characteristics relating to, for example, body size, personality and health. Changes in DNA methylation are proposed to be the mechanistic link between the early-life conditions and determining later-life health and survival. Through this study, we seek to better understand how urban-dwelling birds are affected – both positively and negatively – by exposure to urban “stressors”. Understanding how and why exposure to stressors in towns and cities may affect health and survival of birds is important for progression of our knowledge of animal biology, implementation of effective conservation measures, and improving our own health and wellbeing.
Oxidative stress is defined as an imbalance of damage-inducing pro-oxidants and the antioxidant defences that can counteract or detoxify these reactive molecules and repair damage. By increasing the oxygen concentration in the atmosphere, our objective was to induce oxidative stress during development in the eggs of a wild bird. While this method has been used to successfully induce oxidative stress in fish and insects, there is no published literature concerning the application to birds. Preliminary analysis of seven different biomarkers has revealed that the experimental manipulation did not induce significant oxidative stress in developing embryos and had no effect on telomere length – a marker of genomic stability and linked to senescence. However, depletion of antioxidants that the mother deposits in the yolk suggests that the yolk buffers the embryo against damage. The study offers a valuable contribution to our understanding of the causes and consequences of oxidative stress during development.
Through the use of state-of-the-art technologies and representing one of a relatively few number of studies applying such techniques to “non-model” organisms, the project has made valuable and novel contributions to the field. The knowledge gained will help to inform future projects and improve available tools and methodologies. The project has resulted in the generation of hugely valuable information for researchers – communicated via invited talks, conference presentations and peer-reviewed publications - and for the laboratories that provide the state-of-the-art services – via extensive discussions during project planning and execution. Labs can use this knowledge to better inform current and future customers about the potential applications and challenges of methods, and to improve methodologies.
Biological sequence data generated by the project has been deposited in an open database, creating opportunities for use by others and thus increasing the impact and potential value of the study. Further data will be deposited upon the publication of results in peer-reviewed journals.