Dr. Christina Bauch - Life history & ageing

Understanding differences in life history and ageing

Species, populations as well as individuals within populations differ in ageing rates, lifespan and other fitness-related characteristics, which consequently affects ecological and evolutionary dynamics. To decipher these processes, it is crucial to identify the molecular and physiological traits associated with fitness and to understand to what extent these traits are genetically determined, subject to age-related changes and influenced by the environment.

Molecular & physiological mechanisms

Telomere length and dynamics

Telomeres consist of evolutionarily conserved DNA sequence repeats that together with specific proteins form the ends of chromosomes. They contribute to chromosome stability and genome integrity. Telomere length and shortening have been emerged as a candidate biomarkers of ageing and phenotypic quality as both traits reflect survival probability in many organisms. Telomere length generally shortens with age, but telomere length and dynamics vary largely between individuals. I am interested to understand the causes and consequences of telomere length variation. More about telomere biology here.

Glucocorticoids

Corticosterone is the main avian glucocorticoid. This hormone rises quickly in response to unpredictable stress (e.g. predation threat or handling) initiating a cascade of physiological mechanisms for a fast fight-or-flight reaction. At baseline levels, corticosterone acts as a metabolic hormone, involved in energy regulation, that allows individuals to cope with predictable changes (e.g. seasonal adaptations, reproduction, moult). I am interested to understand how corticosterone (or cortisol in most mammals) interacts with associated mechanisms for individuals to adapt to environmental challenges and the relationship with ageing or senescence.

Oxidative stress

Oxidative stress in the cell reflects an imbalance between damaging reactive oxygen species that are produced during aerobic energy production and counteracting antioxidant defence mechanisms. Oxidative stress can cause toxic effects through peroxides and free radicals that damage all components of a cell. It has been associated with senescence in different taxa. Increased oxidative stress has been shown to accelerate telomere attrition in cell cultures, whereas this relationship is still unclear in vivo.

Metabolism / blood metabolites

Metabolism is the set of life-sustaining chemical reactions in an organism. I am interested to understand genetically and environmentally induced inter-individual differences and the relationship with ageing rates and fitness and investigate the use of blood metabolite concentrations as indicators of body condition, performance and health.

Life-history trade-offs

Where resources and the time it takes to acquire them are limiting, life history theory predicts a trade-off in the investment into energetically costly activities such as growth, reproduction and self-maintenance. In different projects I investigate(d) life history trade-offs and underlying mechanisms using different approaches: cross-sectional (population level), longitudinal (within-individual), correlational and experimental.

Publications on the topic:

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Inheritance

Telomere length varies between individuals from early life onwards. In the framework of long-term research project on free-living jackdaws we investigated inheritance patterns of telomere length and telomere dynamics. The multigenerational pedigree and experimental cross-fostering allow us to disentangle genetic from environmental influences on telomere length. We use quantitative genetic tools ('animal models') to identify which and to what extent genetic and environmental components contribute to telomere length variation.

Publications on the topic:

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jackdaw pedigree (telomere data; maternal & paternal links)