A reassessment of the genome size-invasiveness relationship in reed canarygrass (Phalaris arundinacea).

Background and Aims: Genome size is hypothesized to affect invasiveness in plants. Key evidence comes from a previous study of invasive eastern North American populations of the grass Phalaris arundinacea: invasive genotypes with smaller genomes had higher growth rates, and genome sizes were smaller in the invasive vs. native range. This study aimed to re-investigate those patterns by examining a broader range of North American populations and by employing the modern best-practice protocol for plant genome size estimation in addition to the previously used protocol. Methods: Genome sizes were measured using both internal and pseudo-internal standardization protocols for 20 invasive and nine native range accessions of P. arundinacea. After a round of vegetative propagation to reduce maternal environmental effects, growth (stem elongation) rates of these accessions were measured in the greenhouse. Key Results: Using the best-practice protocol, there was no evidence of a correlation between genome size and growth rates (P = 0.704), and no evidence for differences in genome sizes of invasive and native range accessions (P > 0.353). However, using the older genome size estimation protocol, both relationships were significant (reproducing the results of the previous study). Conclusions: Genome size reduction has not driven increased invasiveness in a broad sample of North American P. arundinacea. Further, inappropriate genome size estimation techniques can create spurious correlations between genome size and plant traits such as growth rate. Valid estimation is vital to progress in understanding the potentially widespread effects of genome size on biological processes and patterns.

Developing Digital Privacy: Children's Moral Judgments Concerning Mobile GPS Devices.

New technology poses new moral problems for children to consider. We examined whether children deem object tracking with a mobile GPS device to be a property right. In three experiments, 329 children (4-10 years) and adults were asked whether it is acceptable to track the location of either one's own or another person's possessions using a mobile GPS device. Young children, like adults, viewed object tracking as relatively more acceptable for owners than nonowners. However, whereas adults expressed negative evaluations of someone tracking another person's possessions, young children expressed positive evaluations of this behavior. These divergent moral judgments of digital tracking at different ages have profound implications for how concepts of digital privacy develop and for the digital security of children.