The primary causes of individual differences in DNA methylation are environmental factors

This 2015 Canadian human study by McGill researchers found: “Differential methylation is primarily non-genetic in origin, with non-shared environment accounting for most of the variance. These non-genetic effects are mainly tissue-specific. The full scope of environmental variation remains underappreciated.” The researchers developed their findings using adipose and blood samples from monozygotic and dizygotic twins in … Continue reading The primary causes of individual differences in DNA methylation are environmental factors

If research treats “Preexisting individual differences” as a black box, how can it find causes for stress and depression?

This 2014 research studied both humans and rodents to provide further evidence on the physiology of defeat. The researchers demonstrated that with mice: “Bone marrow transplants of stem cells that produce leucocytes lacking IL-6 (the cytokine interleukin 6) or when injected with antibodies that block IL-6 prior to stress exposure, the development of social avoidance … Continue reading If research treats “Preexisting individual differences” as a black box, how can it find causes for stress and depression?

Group statistics don’t necessarily describe an individual

I’m curating this 2018 UC Berkeley/Drexel/Netherlands analysis of human studies via its press coverage. The authors: “Collaborated to analyze data on hundreds of adults – some mentally or physically sound, others suffering from various conditions such as depression, anxiety, or post-traumatic stress disorder. Participants had completed surveys about their mental health and had their heart … Continue reading Group statistics don’t necessarily describe an individual

Do our unique visual perceptions arise from brain structural differences?

This 2014 UK/German human study involved fMRI scans of the subjects inferior temporal cortex while viewing images: “Brain representational idiosyncrasies accessible to fMRI are expressed in an individual’s perceptual judgments. We found evidence for an individually unique representation predictive of perceptual idiosyncrasies in hIT [human inferior temporal cortex] (but not in early visual areas) and … Continue reading Do our unique visual perceptions arise from brain structural differences?

Do genes or maternal environments shape fetal brains?

This 2019 Singapore human study used Diffusion Tensor Imaging on 5-to-17-day old infants to find: “Our findings showed evidence for region-specific effects of genotype and GxE on individual differences in human fetal development of the hippocampus and amygdala. Gene x Environment models outcompeted models containing genotype or environment only, to best explain the majority of … Continue reading Do genes or maternal environments shape fetal brains?

Statistical inferences vs. biological realities

A 2019 UCLA study introduced a derivative of the epigenetic clock named GrimAge: “DNAm GrimAge, a linear combination of chronological age, sex, and DNAm-based surrogate biomarkers for seven plasma proteins and smoking pack-years, outperforms all other DNAm-based biomarkers, on a variety of health-related metrics. An age-adjusted version of DNAm GrimAge, which can be regarded as … Continue reading Statistical inferences vs. biological realities

A trio of epigenetic clock studies

We’ll start with a 2018 epigenetic clock human study from Finland: “We evaluated the association between maternal antenatal depression and a novel biomarker of aging at birth, namely epigenetic gestational age (GA) based on fetal cord blood methylation data. We also examined whether this biomarker prospectively predicts and mediates maternal effects on early childhood psychiatric … Continue reading A trio of epigenetic clock studies

The lifelong impact of maternal postpartum behavior

This 2018 French/Italian/Swiss rodent study was an extension of the work done by the group of researchers who performed Prenatal stress produces offspring who as adults have cognitive, emotional, and memory deficiencies and Treating prenatal stress-related disorders with an oxytocin receptor agonist: “Reduction of maternal behavior [nursing behavior, grooming, licking, carrying pups] was predictive of … Continue reading The lifelong impact of maternal postpartum behavior

Sex-specific impacts of childhood trauma

This 2018 Canadian paper reviewed evidence for potential sex-specific differences in the lasting impacts of childhood trauma: “This paper will provide a contextualized summary of neuroendocrine, neuroimaging, and behavioral epigenetic studies on biological sex differences contributing to internalizing psychopathology, specifically posttraumatic stress disorder and depression, among adults with a history of childhood abuse. Given the … Continue reading Sex-specific impacts of childhood trauma

Obtaining convictions with epigenetic statistics?

This 2018 Austrian review subject was forensic applications of epigenetic clock methodologies: “The methylation-sensitive analysis of carefully selected DNA markers (CpG sites) has brought the most promising results by providing prediction accuracies of ±3–4 years, which can be comparable to, or even surpass those from, eyewitness reports. This mini-review puts recent developments in age estimation … Continue reading Obtaining convictions with epigenetic statistics?