The truth about complex traits and GWAS

This 2017 Colorado analysis, “No Evidence That Schizophrenia Candidate Genes Are More Associated With Schizophrenia Than Noncandidate Genes,” found: “A recent analysis of 25 historical candidate gene polymorphisms for schizophrenia in the largest genome-wide association study [GWAS] conducted to date suggested that these commonly studied variants were no more associated with the disorder than would be … Continue reading The truth about complex traits and GWAS

What drives cellular aging?

This 2019 US/UK human cell study by the founder of the epigenetic clock method investigated epigenetic aging: “It is widely assumed that extension of lifespan is a result of retardation of ageing. While there is no counter-evidence to challenge this highly intuitive association, supporting empirical evidence to confirm it is not easy to acquire. The … Continue reading What drives cellular aging?

Epigenetic clock statistics and methods

This 2018 Chinese study was a series of statistical and methodological counter-arguments to a previous epigenetic clock study finding that: “Only [CpG] sites mapping to the ELOVL2 promoter constitute cell and tissue-type independent aDMPs [age-associated differentially methylated positions].” The study used external data sets and the newer epigenetic clock’s fibroblast data in its analyses to … Continue reading Epigenetic clock statistics and methods

Hidden hypotheses of epigenetic studies

This 2018 UK review discussed three pre-existing conditions of epigenetic genome-wide association studies: “Genome-wide technology has facilitated epigenome-wide association studies (EWAS), permitting ‘hypothesis-free’ examinations in relation to adversity and/or mental health problems. Results of EWAS are in fact conditional on several a priori hypotheses: EWAS coverage is sufficient for complex psychiatric problems; Peripheral tissue is … Continue reading Hidden hypotheses of epigenetic studies

Common features of autoimmune diseases

This 2018 French review subject was mechanisms of autoimmunity: “Autoimmune diseases (AIDs) encompass more than 80 distinct chronic disorders characterized by inflammatory reactions that can either be systemic or organ specific. In all cases, the disease development is the consequence of the effects of environmental factors in predisposed individuals. Most of the genes identified by … Continue reading Common features of autoimmune diseases

Resiliency in stress responses

This 2018 US Veterans Administration review subject was resiliency and stress responses: “Neurobiological and behavioral responses to stress are highly variable. Exposure to a similar stressor can lead to heterogeneous outcomes — manifesting psychopathology in one individual, but having minimal effect, or even enhancing resilience, in another. We highlight aspects of stress response modulation related … Continue reading Resiliency in stress responses

A study of gene-environment interactions

This 2018 Hungary/UK study used Bayesian analysis to better understand gene-environment interactions that produce depression: “Most genetic studies do not consider the effect of stressors which may be one reason for the lack of replicable results in candidate gene studies, GWAS [genome-wide association studies] and between human studies and animal models..Animal models of depression usually … Continue reading A study of gene-environment interactions

DNA methylation and childhood adversity

This 2017 Georgia human review covered: “Recent studies, primarily focused on the findings from human studies, to indicate the role of DNA methylation in the associations between childhood adversity and cardiometabolic disease in adulthood. In particular, we focused on DNA methylation modifications in genes regulating the hypothalamus-pituitary-adrenal axis as well as the immune system.” Recommendations … Continue reading DNA methylation and childhood adversity

Epigenetics research and evolution

This 2017 UK essay was a longish review of how epigenetics and other research has informed evolutionary theory: “There are several processes by which directed evolutionary change occurs – targeted mutation, gene transposition, epigenetics, cultural change, niche construction and adaptation. Evolution is an ongoing set of iterative interactions between organisms and the environment. Directionality is … Continue reading Epigenetics research and evolution

A review of biological variability

This 2017 UK/Spanish review subject was biological variability: “No two cells in a cellular population are the same, and no two individuals of a multi-cellular species are identical-not even if they share the same genetic makeup like monozygotic twins or cloned animals. Epigenetic and gene expression variability are key contributors to phenotypic differences. There are … Continue reading A review of biological variability