Biology subjects

Steiner, U.

Publications and source records attributed to Steiner, U..

2 recordsLinked to original sources

bioRxiv2018

Quantifying genetic, environmental and individual stochastic variability in Plantago lanceolata

Predicting ecological and evolutionary population dynamics requires understanding how genetic and environmental parameters influence variation in survival and reproduction among individuals. However such a focus often neglects the stochastic events that individuals experience throughout their lives that also influence survival and reproduction. With an illustrative example, we quantify and illustrate the influence of such non-selective demographic variability on population dynamics using size-structured matrix models of an experimental population of Plantago lanceolata. Our analysis shows that variation in survival and reproduction among individuals explained by environment, genes, and their interaction was modest compared to the stochastic variation in lifespan and reproduction. We illustrate how expectations on population growth, based on expected lifetime reproduction and generation time, can be misleading when variance in reproduction among individuals of the same genotype (full sibs) was large. Such large within genotype variance can lower population growth, fitness. Our results accompany recent investigations that call for more focus on stochastic variation in survival and reproduction, rather than dismissal of this variation as uninformative noise.

evolutionary biology↗

bioRxiv2017

Parallel progress in perceived age and life expectancy

Human life expectancy continues to rise in most populations. This rise not only leads to longer lives but is also accompanied by improved health at a given age, i.e. we see a reduction of biological age for a given chronological age in recent cohorts. Despite or even because of the diversity of biomarkers of aging, an accurate quantification of a general shift in biological age across time has been challenging. By comparing age perception of images taken in 2001 over a decade, we show that age perception changes substantially across time and parallels the progress in life expectancy. In 2012, people aged 70+ needed to look 2.3 years younger to be rated the same age as in 2002. Our results further suggest that age perception reflects the past life events better than predicts future length of life, i.e. it is written in your face how much you have aged so far, but does not predict well how fast you will age in the future. We draw this conclusion since age perception among elderly paralleled changes in life expectancy at birth but not changes in remaining life expectancies. We illustrate advantages of perceived age as a biomarker of aging and suggest that changes in age perception should be explored for younger age classes to inform on aging processes, including whether aging is delayed or slowed with increasing life expectancy.

epidemiology↗