This 2020 review by a Hong Kong company’s researchers compared and contrasted measures of biological age: “More than a dozen aging clocks use molecular features to predict an organism’s age, each of them utilizing different data types and training procedures. We offer a detailed comparison of existing mouse and human aging clocks, discuss their technological … Continue reading Linear thinking about biological age clocks
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
This 2016 US/Italy article was written from the perspective of regenerative bioengineering: “Higher levels beyond the molecular can have their own unique dynamics that offer better (e.g. more parsimonious and potent) explanatory power than models made at lower levels. Biological systems may be best amenable to models that include information structures (organ shape, size, topological … Continue reading A top-down view of biological goal-directed mechanisms
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
This 2015 Zurich human review addressed: “A remarkable lack of discussion on the meaning and interpretation of frequently used hormone ratios. The interpretation of hormone ratios is complicated and in many cases not sufficiently supported from a theoretical point of view. Based on the assumption that the balance between two interdependent hormones determines their eventual … Continue reading Are hormone ratios useful in explaining health? Behavior? Neurobiology? Anything?
How Trauma and Resilience Cross Generations “The purpose of epigenetic changes, I think, is simply to increase the repertoire of possible responses. So let’s say, for some reason, your parents transmitted to you biologic changes that are very appropriate to starvation, but you don’t live in a culture where food is not plentiful. You’re just … Continue reading An interview with Dr. Rachel Yehuda on biological and conscious responses to stress
I curated this 2015 Georgia human study only for its use of two methods of estimating biological age. The researchers misguidedly used these techniques to help paint a scientific patina on an agenda. One of the methods was originated by a coauthor of The degree of epigenetic DNA methylation may be used as a proxy … Continue reading Using epigenetic DNA methylation markers to estimate biological age
This 2015 New Zealand human study used the same subjects of the More from the researchers that found people have the same personalities at age 26 that they had at age 3 study. The researchers used 10 biologic age markers of the subjects at age 38 to find that their biological ages ranged from 28 … Continue reading A study of biological aging in young adults with limited findings
This 2015 Harvard/MIT rodent study was of long (more than 200 nucleotides) noncoding (non-protein coding) RNAs (ribonucleic acids). These are of interest because: “Within the mammalian body, the largest repertoire and diversity of lncRNA genes outside the germ line occurs in the brain, where lncRNAs exhibit regional and cell-specific localization. The expression patterns of lncRNAs … Continue reading RNA as a proxy signal for context-specific biological activity
This fascinating 2014 human study developed the new use of a somewhat intuitive marker of aging. The researchers used the degree of methylation – an epigenetic chemical modification of DNA – as an epigenetic clock to measure biological age. The researchers found that, on average, the epigenetic age of the liver increased by 3.3 years … Continue reading The degree of epigenetic DNA methylation may be used as a proxy to measure biological age
