Epigenetics

From Institute for Basic Science: When spring is approaching, how do plants decide that it is time to flower? A team of plant scientists led by KWAK June M. at the Center for Plant Aging Research, within the Institute for Basic Science (IBS) unravelled a new mechanism to explain this seemingly easy, but actually complicated question. Their research was published in the Proceedings of the National Academy of Sciences (PNAS) on November 11, 2016. … Epigenetic regulation is one of the major mechanisms to control flowering time. It regulates gene expression through chemical modifications of DNA and its interacting proteins, but without changing the DNA sequence. If you think of the DNA contained in each cell as a big book Read More ›

From science writer Philip Ball at Physics: How does a liver cell remember that it’s a liver cell when it replicates? A cell’s identity is determined in part by small molecules that bind to chromosomes at specific locations. Now researchers have devised a model that seems to explain how these so-called epigenetic patterns are sustained across generations of cells. The model connects the epigenetic marking of genes with the three-dimensional structure of DNA as it is folded up inside chromosomes. It leads to a mechanism for patterns of markings to be repaired if they are disturbed by events such as gene replication. Epigenetic markings are small molecules added onto parts of chromosomes that may act as genetic switches, silencing some Read More ›

From Nathaniel Comfort at Aeon: While inflated medical promises are hardly peculiar to molecular medicine, that field does seem particularly prone to breathless rhetoric. You can almost hear K Eric Drexler panting when he writes, in his manifesto Engines of Creation (1986), that protein-based nanomachines ‘promise to bring changes as profound as the Industrial Revolution, antibiotics, and nuclear weapons all rolled up in one massive breakthrough’. Bluster, overstatement and aspirations masquerading as hard targets have no single cause. One reason, surely, is the heady sense of impending omnipotence that accompanies major technological and scientific advances. Charles Darwin’s theory of evolution by natural selection, the rediscovery of Gregor Mendel’s laws of heredity, the cracking of the genetic code, genetic engineering, the Read More ›

From astronomer and physicist Milan Ćirković at Nautilus: When H.G. Wells wrote about aliens, his wild imaginings were shaped by Darwin’s theory of evolution. In The War of the Worlds, giant Martian invaders with whip-like arms are threatened by extinction and so expand into a new ecological niche by colonizing other planets, notably Earth. In The Time Machine, a time traveler visiting the future stumbles upon two posthuman species. What led Wells to these majestic speculations, inspiring science-fiction buffs and also many scientists to this day? A firm belief in the universality of evolution by natural selection. But does evolution operate the same on life everywhere? The success of Darwinian theory to explain life on Earth has lulled many of Read More ›

From ScienceDaily: The increased risk of hyperglycemia associated with prenatal exposure to famine is also passed down to the next generation, according to a new study of hundreds of families affected by widespread starvation in mid-20th Century China. … Among 983 people gestated during the famine years, 31.2 percent had hyperglycemia and 11.2 percent had type 2 diabetes. By comparison, among 1,085 people gestated just after the famine ended, the prevalence of hyperglycemia was 16.9 percent, and the prevalence of type 2 diabetes as 5.6 percent. Controlling for factors such as gender, smoking, physical activity, calorie consumption and body-mass index, the researchers calculated that in utero famine exposure was associated with 1.93-times higher odds of hyperglycemia and a 1.75 times Read More ›

From University of Bergen: A new Norwegian diet intervention study (FATFUNC), performed by researchers at the KG Jebsen center for diabetes research at the University of Bergen, raises questions regarding the validity of a diet hypothesis that has dominated for more than half a century: that dietary fat and particularly saturated fat is unhealthy for most people. The researchers found strikingly similar health effects of diets based on either lowly processed carbohydrates or fats. In the randomized controlled trial, 38 men with abdominal obesity followed a dietary pattern high in either carbohydrates or fat, of which about half was saturated. Fat mass in the abdominal region, liver and heart was measured with accurate analyses, along with a number of key Read More ›

Whether anyone admits it or not. From Jef Akst at The Scientist on the recent appearance of many papers on epigenetics: Last week (November 17), the International Human Epigenome Consortium (IHEC) published 41 papers in Cell Press journals and other high-impact publications. IHEC aims to provide researchers with a comprehensive epigenomic analysis of healthy and abnormal cells, and the new studies constitute major strides toward that goal. … “The number of papers and variety of topics addressed by this creative team of scientists from around the globe not only reflects the dynamic nature of this consortium, but is also evidence of the great strength that comes from bringing together complementary expertise, with the potential for far greater impact than an Read More ›

From ScienceDaily: Those with both rare and common types of autism spectrum disorder share a similar set of epigenetic modifications in the brain, according to a study. More than 68% of individuals with different types of autism spectrum disorder show evidence of the same pattern of a chemical modification of the protein scaffold around which DNA wraps. The findings suggest that a single global epigenetic pattern affecting shared molecular pathways in the brain could underlie diverse manifestations of this psychiatric disease. “We find epigenetic changes that are present in most patients with autism spectrum disorder, or ASD,” says co-senior study author Shyam Prabhakar of the Genome Institute of Singapore. “This suggests that, despite tremendous heterogeneity in the primary causes of Read More ›

Comprehensive for now. From ScienceDaily: One of the great mysteries in biology is how the many different cell types that make up our bodies are derived from a single cell and from one DNA sequence, or genome. We have learned a lot from studying the human genome, but have only partially unveiled the processes underlying cell determination. The identity of each cell type is largely defined by an instructive layer of molecular annotations on top of the genome — the epigenome — which acts as a blueprint unique to each cell type and developmental stage. Unlike the genome the epigenome changes as cells develop and in response to changes in the environment. Defects in the factors that read, write, and Read More ›

From ScienceDaily: Repeated binge drinking during adolescence can affect brain functions in future generations, potentially putting offspring at risk for such conditions as depression, anxiety, and metabolic disorders, a Loyola University Chicago Stritch School of Medicine study has found. “Adolescent binge drinking not only is dangerous to the brain development of teenagers, but also may impact the brains of their children,” said senior author Toni R. Pak, PhD, an associate professor in the Department of Cell and Molecular Physiology of Loyola University Chicago Stritch School of Medicine. … The study, which was based on an animal model, found that adolescent binge drinking altered the on-off switches of multiple genes in the brains of offspring. When genes are turned on, they Read More ›

From ScienceDaily: In a study on two groups of parasites, the team detected differences in DNA sequences that could be attributed to the composition of their food. … ‘We found that different levels of nitrogen in a parasite’s diet contributed to changes in its DNA. Specifically, parasites with low-nitrogen, high-sugar diets had DNA sequences that used less nitrogen than parasites with nitrogen-rich, high-protein diets.’ The study involved groups of eukaryotic parasites (Kinetoplastida) and bacterial parasites (Mollicutes) that infect different plant or animal hosts. The results, based on novel mathematical models developed by the researchers, reveal a previously hidden relationship between cellular metabolism and evolution. They provide new insights into how DNA sequences can be influenced by adaptation to different diets. Read More ›

From Michael Skinner at Aeon: Darwin’s theory that natural selection drives evolution is incomplete without input from evolution’s anti-hero: Lamarck If sneers had weight, the Darwinian sneers against Lamarck over the last century or so would have crushed the Royal Society building to rubble. Let’s remember that when we hear bafflegab PR about how nothing has changed. When we read stuff like this, a lot of things have changed. One problem with Darwin’s theory is that, while species do evolve more adaptive traits (called phenotypes by biologists), the rate of random DNA sequence mutation turns out to be too slow to explain many of the changes observed. Scientists, well-aware of the issue, have proposed a variety of genetic mechanisms to Read More ›

Who thought twenty years ago we’d be reading science releases like this ? From Jeffrey M. Perkel at The Scientist: The idea of establishing an ant colony as a model system for epigenetics dates back nearly 12 years to a conversation Reinberg had with Shelley Berger, an epigeneticist at the University of Pennsylvania. Berger had recently returned from a family vacation in Costa Rica, where she spent time watching leaf-cutter ants in action. Ant colonies are highly homogeneous, genetically speaking. Yet their members vary dramatically in shape, size, and behavior. “In some cases the worker and queen are absolutely identical genetically, and yet they have completely different functions,” Berger explains. “The workers give up their reproduction to the queen.” Such Read More ›

From ScienceDaily: Smoking leaves its “footprint” on the human genome in the form of DNA methylation, a process by which cells control gene activity, according to new research in Circulation: Cardiovascular Genetics, an American Heart Association journal. … “These results are important because methylation, as one of the mechanisms of the regulation of gene expression, affects what genes are turned on, which has implications for the development of smoking-related diseases,” said Stephanie J. London, M.D., Dr.P.H., last author and deputy chief of the Epidemiology Branch at the National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina. “Equally important is our finding that even after someone stops smoking, we still see the effects of smoking Read More ›

From ScienceDaily: New findings published in eLife draw connections between some of these pieces, revealing an extensive web of molecular interactions that may ultimately inform the development of new epigenetic drugs for cancer and other diseases. Specifically, the study reveals a mechanism that helps explain how dividing cells pass patterns of epigenetic information called methyl tags to their daughter cells, a crucial part of regulating gene expression across cell generations. Epigenetic tags help tell genes — stretches of DNA that act as biological instruction manuals — when to switch “on” and “off,” ultimately determining cell type and function. DNA methylation, or the addition of methyl tags to DNA, is one of the most well-studied epigenetic signals; errors in this process Read More ›