Sleep-wake rhythms vary widely among individuals and between age groups
Our circadian systems synchronize with light and darkness in the environment, giving rise to chronotypes: individual rhythms in physiology, cognition and behavior. In a new PLOS ONE study, researchers analyzed self-reported data from over 50,000 U.S. respondents to examine how individual chronotypes vary.
The researchers found that individual chronotypes vary by as much as 10 hours. Interestingly, on average women’s biological “day” started earlier than men’s during the first half of their lives. Teenagers’ biological “day” started later than adults’, such that high school students are effectively starting school hours in their biological “night.” These findings may support delaying school start times, as well as tailoring work schedules to individuals’ chronotypes, to optimize health.
First chikungunya-infected mosquito found in Brazil
Chikungunya virus often causes fever and joint pain, and while it is endemic in Africa and Asia, it was only detected in Brazil in 2014. Now, researchers reporting in PLOS Neglected Tropical Diseases have identified the first Brazilian mosquito — caught in the Brazilian city of Aracaju — found to be naturally infected with chikungunya.
The scientists collected and tested 248 mosquitos from inside and outside Aracaju homes where residents reported symptoms consistent with chikungunya. They found a female Aedes aegypti mosquito that was infected with the East/Central/South African genotype of chikungunya, and call for increasing monitoring of this species to prevent new chikungunya outbreaks.
Coronary artery disease genes may aid childbearing
Coronary artery disease may have plagued humans for thousands of years, and it was previously unclear why natural selection has not removed genes for this disease. In a new PLOS Genetics study, researchers analyzed genetic information and lifetime reproductive data and found that genes associated with coronary artery disease also contribute in multiple ways to greater male and female reproductive success.
The findings may explain why natural selection cannot weed out genes associated with coronary artery disease – their presence is an evolutionary trade-off that provides early-life reproductive benefits that compensate for later-life disease costs. Parents pass these genes on to their offspring before experiencing coronary artery disease symptoms and death.
Image Credit: NIAID, Flickr
Costa-da-Silva AL, Ioshino RS, Petersen V, Lima AF, Cunha MdP, Wiley MR, et al. (2017) First report of naturally infected Aedes aegypti with chikungunya virus genotype ECSA in the Americas. PLoS Negl Trop Dis 11(6): e0005630. https://doi.org/10.1371/journal.pntd.0005630
Byars SG, Huang QQ, Gray L-A, Bakshi A, Ripatti S, Abraham G, et al. (2017) Genetic loci associated with coronary artery disease harbor evidence of selection and antagonistic pleiotropy. PLoS Genet 13(6): e1006328. https://doi.org/10.1371/journal.pgen.1006328