The Lansing effect in Lemna turionifera (Lemnoideae) and potential contributing factors
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University of Lethbridge. Faculty of Arts and Science
Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences
The Lansing effect is a specific type of parental age effect whereby older parents have shorter-lived offspring than younger parents. The phenomenon is important because it implies the presence of non-genetic forms of inheritance relating to parental age, such as epigenetics or physiological effects. Further, the existence of the Lansing effect informs our understanding of the evolution of life histories because it shows that senescence – traditionally defined in terms of decreases in survival and reproduction with age – also involves a decrease in offspring quality. The Lansing effect has been observed in a wide variety of taxa, including plants. Here, I investigated the Lansing effect in the subfamily Lemnoideae (duckweeds). My objectives were two-fold: (1) testing for the Lansing effect, and (2) if the Lansing effect is present, determining whether shortened lifespans of offspring of older parents are due to a higher mortality rate at all ages (i.e. a difference in baseline mortality), or a faster-accelerating mortality with age. I recorded lifespan, reproduction, and other metrics of fitness of 392 individuals; half were their parent’s first clonal offspring (offspring of younger parents), and half were fifth clonal offspring (offspring of older parents). Offspring of older parents had shorter lifespans (i.e., the Lansing effect occurred) and produced fewer offspring themselves compared to offspring of younger parents. Further, a model-selection approach indicated that offspring of older parents had a greater initial mortality rate at birth that then persisted through life compared to offspring of younger parents. Thus, greater baseline mortality was responsible for the Lansing effect for the plants in this experiment. My work emphasizes that senescence can manifest in offspring as a result of parental age effects, specifically the Lansing effect, in addition to the more well described phenomena of decreasing survival and reproduction.
Lansing effect , duckweed , Lemna turionifera , parental age effect , senescence , decreasing offspring quality , older parents , offspring of older parents