A preliminary investigation of epigenome-wide DNA methylation and temperament during infancy

This study provides preliminary evidence for an epigenetic architecture of infant temperament. At 12 months of age, blood was collected and assayed for DNA methylation and maternally reported infant temperament was assessed using the Infant Behavior Questionnaire in 67 mother-infant dyads. Epigenome-wide analyses showed that the higher order temperament dimensions Surgency and Negative Affect were associated with DNA methylation. The epigenetic signatures of Surgency and Negative Affect were situated at genes involved in synaptic signaling and plasticity. Although replication is required, these results are consistent with a biologically based model of temperament, create new avenues for hypothesis-driven research into epigenetic pathways that underlie individual differences in temperament, and demonstrate that infant temperament has a widespread epigenetic signature in the methylome.

Demographic and health predictors of telomere length during adolescence

Telomere length (TL) is proposed to play a mechanistic role in how the exposome affects health outcomes. Little is known about TL during adolescence, a developmental period during which precursors of adult-onset health problems often emerge. We examined health and demographic sources of variation in TL in 899 youth aged 11-17. Demographic and health information included age, sex, race, household income, caregiver age and marital status, youth tobacco exposure, body mass index, pubertal status, health problems, medication use, and season of data collection. Genomic DNA was extracted from saliva, and T/S ratios were computed following qPCR. Age, race, season of data collection, and household income were associated with the telomere to single copy (T/S) ratio. We found that T/S ratios were larger at younger ages, among Black youth, for saliva collected during autumn and winter, and among households with higher income. Analyses stratified by race revealed that the association between age and T/S ratio was present for Black youth, that season of collection was present across races, but that family demographic associations with T/S ratio varied by race. The results provide information for future telomere research and highlight adolescence as a potentially important developmental phase for racial disparities in telomere shortening and health.

The influence of exercise on anxiety-like behavior in zebrafish (Danio rerio)

In non-human mammals, exercise has been shown to decrease anxiety-like behavior. Conversely, a number of studies have reported no effect or even an increase in anxiety-like behavior after exercise, however, inconsistent training regimes and behavioral paradigms across studies may be confounding the results. Zebrafish (Danio rerio) are a well-established animal model in neurobehavioral research, and have the potential to shed new insight into the effects of exercise on anxiety-like behavior where previous research has been limited, due to the ability to precisely control intensity and duration of exercise, and the validation of tests for measuring different aspects of anxiety-like behaviors. In the current study, fish were split between two treatment groups; Exercised and Control. Fish in the exercised condition were aerobically challenged (max water velocity: 0.5 m/s) using a swim tunnel one hour a day, five days a week, for six weeks. Control fish spent an equal amount of time in the swim tunnel but were not aerobically challenged (max water velocity: 0.05 m/s). After six weeks, all fish were tested individually in two standard complimentary anxiety tests for zebrafish: the novel tank test and the light-dark test. Exercised fish exhibited reduced anxiety-like behaviors in the novel tank test; they spent more time in the top and were quicker to enter the top of a novel tank compared to Control fish. In addition, Exercised fish spent more time in the light compartment of the light-dark test compared to Control fish. Our results demonstrate the beneficial effect of exercise on anxiety-like behavior in zebrafish.