Collaborative Research: Parental Effects, Telomere Dynamics, and the Cross-Generational Effects of Stressors

Many organisms are expected to experience greater stress exposure in the face of rapid environmental change. The effects of stress can alter parents in ways that can cause changes in offspring phenotype, with potentially both positive and negative effects on fitness. Such cross-generational effects of stress exposure are likely to be critical to predicting the long-term impacts of environmental change. Parents commonly influence offspring via changes in parental behavior, the transmission of signaling factors to embryos, and changes in the control of DNA expression. An alternative that has yet to be tested is that stress responses in parents could directly impact the DNA that offspring inherit, with lifetime consequences for the offspring. This could occur if stress experienced by parents affects telomere length in their gametes, which then influence telomere length in offspring. Telomeres are highly conserved repetitive segments of DNA, and their length affects cellular and organismal aging. Thus direct cross-generational transmission of stress effects on telomeres may have lifetime consequences. This proposal outlines a program of study that will test the direct transmission of effects on telomeres and assess the long-term consequences of this, and also some of the indirect pathways by which stress affects offspring. The study will employ a series of experiments on free-living and captive house sparrows and analysis of archived blood samples and data from a long-term study.