Check out our highlights from the PLOS Computational Biology November issue:
Tracking urban human activity from mobile phone calling patterns
For humans living in urban areas, modern daily life is very different from that of people who lived in ancient times, from which today’s societies evolved. Mainly due to the availability of artificial lighting, modern humans have been able to modify their natural daily cycles. In addition, social rules, like those related to work and schooling, tend to require specific schedules for the daily activities. However, it is not fully understood to what extent the seasonal changes in sunrise and sunset times and the length of daylight could influence the timings of these activities. In this study, Daniel Monsivais and colleagues use a new approach to describe the dynamics of human resting periods in terms of mobile phone calling activity, showing that the onset and termination of the resting pattern of urban humans follow the east-west sun progression inside the same timezone. Also they found that the onset of the low calling activity period, as well as its mid-point, are subject to seasonal changes, following the same dynamics as solar midnight. Moreover, with resting time measured as the low activity periods of people in cities, they discovered significant behavioural differences between different age and gender cohorts. These findings suggest that the length and timings of human daily rhythms still have a sensitive dependence on the seasonal changes of the sunlight.
Significant associations between driver gene mutations and DNA methylation alterations across many cancer types
Mutations that alter the function of driver genes by changing DNA nucleotides have been recognized as key players in cancer progression. However, recent evidence has shown that DNA methylation, which can control gene expression, is also highly dysregulated in cancer and contributes to carcinogenesis. Whether methylation alterations correspond to mutated driver genes in cancer remains unclear. In this study, Laura Elnitski and colleagues analyzed 4,302 tumors from 18 cancer types and demonstrated that driver gene mutations are inherently connected with the aberrant DNA methylation landscape in cancer. They showed that driver gene-associated methylation patterns can classify heterogeneous tumors within a cancer type into homogeneous subtypes and have the potential to influence genes that contribute to tumor growth. This finding could help us better understand the fundamental connection between driver gene mutations and DNA methylation alterations in cancer, and to further improve cancer treatment.
Identifying influential neighbors in animal flocking
Schooling fish exhibit impressive group-level coordination in which multiple individuals move together in a seamless way. This is possible because each individual in the group responds to the movement of other group members. But how many individuals does each fish pay attention to? Which are the influential neighbors? Guy Theraulaz and colleagues answer these questions in order to understand how directional information propagates across a group. Their research shows that in the rummy-nose tetra species there is a limited number of influential neighbors which are not necessarily the closest ones.