“..today we must assume that if our generation is suffering hardship, violence or the like, not only will we struggle to forget these difficult periods ourselves but our genes too will remember them, carrying traces to be passed on to the next generation or even several generations.”
From the 8 May 2015 post at Scilogs
The science behind a rapid paradigm shift
When the first human genome was decoded, popular thinking went: “If we know the genes, we know the person.” Today, barely 15 years later, science is in the middle of an exciting new area of research, which is entertaining interested members of the public with exciting, if not always serious, headlines. The field alleges that traumatic experiences can be passed down through the generations and even significantly affect the lives of grandchildren. As it turns out, the reality is that genes not only control, but are also controlled. And that is what epigenetics is all about – how are genes controlled and what factors can influence them?
Epigenetics refers to the meta-level of genetic regulation. Under the influence of external factors, epigenetic mechanisms regulate which genes are turned on and off. This helps our fixed genetic material to be more flexible. At the biochemical micro level, epigenetic regulators are responsible for how closely packed individual genomic regions are and therefore how accessible or not they are. This works by small adhered or detached chemical groups. The resulting marking of the genome is read by specialised enzymes that then cause the switching on or off of the genes.
As reasonable as this appears, one consequence is that we will have to say goodbye to a long-established dogma: the idea that genes are immutable in the creation of a living being. And, looking back through the history of science: was Lamarck right, after all? The 19th-century French biologist had claimed that organisms acquired traits to pass on to future generations . It is precisely this mechanism that epigeneticists are on the trail of today. Laboratory experiments with mice have demonstrated that a particular, targeted encoding of individual genes results in the changes being passed on to the offspring. Epigenetic changes, however, are so-called soft changes, as they can be undone. And that is medicine’s great hope – to be able to intervene in the control mechanism from the outside in order to be able to work against, for example, senile dementia.
At this point, the level of possible tension around this new field of research becomes clear. On the one hand, the idea that our human condition can be so strongly “manipulated” by environmental influences can be very disturbing. And rightly so. Previously, we may have had the upbeat expectation that although we are experiencing suffering, the next generation will have it better. However, today we must assume that if our generation is suffering hardship, violence or the like, not only will we struggle to forget these difficult periods ourselves but our genes too will remember them, carrying traces to be passed on to the next generation or even several generations.
A study often mentioned in this context is based on the analysis of data collected in the Netherlands over the years of hunger in 1944-45, during which the population there suffered particularly difficult conditions. The children born at this time were not only smaller, but, as adults, had an increased risk of obesity, cardiovascular problems and neuropsychiatric disorders. In turn, their offspring were again smaller than average – despite food being in ready supply and living conditions having greatly improved.
Toronto scientists uncovered how viral remnants helped shape control of our genes.
If genes were lights on a string of DNA, the genome would appear as an endless flicker, as thousands of genes come on and off at any given time. Tim Hughes, a Professor at the University of Toronto’s Donnelly Centre, is set on figuring out the rules behind this tightly orchestrated light-show, because when it fails, disease can occur.
Genes are switched on or off by proteins called transcription factors. These proteins bind to precise sites on the DNA that serve as guideposts, telling transcription factors that their target genes are nearby.
In their latest paper, published in Nature Biotechnology, Hughes and his team did the first systematic study of the largest group of human transcription factors, called C2H2-ZF.
Despite their important roles in development and disease, these proteins have been largely unexplored because they posed a formidable challenge for researchers.
C2H2-ZF transcription factors count over 700 proteins — around three per cent of all human genes! To make matters more complicated, most human C2H2-ZF proteins are very different from those in other organisms, like those in mice. This means that scientists could not apply insights gained from animal studies to human C2H2-ZFs.
Hughes’ team found something remarkable: the reason C2H2-ZFs are so abundant and diverse — which makes them difficult to study — is that many of them evolved to defend our ancestral genome from damage caused by the notorious “selfish DNA.”
From the 27 January 2014 ScienceDaily article
“These studies have revealed that single gene mutations can alter the ability of an organism to utilize a specific diet. In humans, small differences in a person’s genetic makeup that change how well these genes function, could explain why certain diets work for some but not others,” said Curran, corresponding author of the study and assistant professor with joint appointments in the USC Davis School of Gerontology, the USC Dornsife College of Letters, Arts and Sciences, and the Keck School of Medicine of USC.
Curran and Pang studied Caenorhabditis elegans, a one-milimeter-long worm that scientists have used as a model organism since the ’70s. Decades of tests have shown that genes in C. elegans are likely to be mirrored in humans while its short lifespan allows scientists to do aging studies on it.
In this study, Curran and Pang identified a gene called alh-6, which delayed the effects of aging depending on what type of diet the worm was fed by protecting it against diet-induced mitochondrial defects.
“This gene is remarkably well-conserved from single celled yeast all the way up to mammals, which suggests that what we have learned in the worm could translate to a better understanding of the factors that alter diet success in humans,” Curran said.
Future work will focus on identifying what contributes to dietary success or failure, and whether these factors explain why specific diets don’t work for everyone. This could be the start of personalized dieting based on an individual’s genetic makeup, according to Curran.
“We hope to uncover ways to enhance the use of any dietary program and perhaps even figure out ways of overriding the system(s) that prevent the use of one diet in certain individuals,” he said.
..a useful resource for students and teachers in grades 9 – 12 to learn genetics.
GeneEd allows students and teachers to explore topics such as Cell Biology, DNA, Genes, Chromosomes, Heredity/Inheritance Patterns, Epigenetics/Inheritance and the Environment, Genetic Conditions, Evolution, Biostatistics, Biotechnology, DNA Forensics, and Top Issues in Genetics.
Teachers can use the site to introduce topics, supplement existing materials, and provide as a reliable source to students conducting research.The site links to categories such as research articles, animation, games, videos, interactive tutorials, and labs and experiments. 3D images, illustrations and text from NHRGI help to enrich the user experience by providing vivid imagery to reinforce genetic concepts.
Text varies from easy-to-read to advanced reading levels, which makes this a versatile tool both in and out of the classroom.
Specialty pages including Teacher Resources and Labs and Experiments highlight those tools that teachers may find particularly helpful.
Other specialty pages such as Careers in Genetics and Highlights allow students to see what is new and noteworthy in the field of Genetics along with links to different careers related to the science of Genetics.
- GeneEd (New Genetics Education Resource from the National Library of Medicine) (bluesyemre.com)
- Ancient human genome completed (stuff.co.nz)
- Arm Yourselves for the Upcoming (Genetics) Revolution (science.kqed.org)
- How much modern genetics should be learnt in school? (wellcometrust.wordpress.com)
- Personal genomics: where science fiction meets reality (csironewsblog.com)
The extent to which our development is affected by nature or nurture – our genetic make-up or our environment – may differ depending on where we live, according to research funded by the Medical Research Council and the Wellcome Trust.
In a study published today in the journal Molecular Psychiatry, researchers from the Twins Early Development Study at King’s College London’s Institute of Psychiatry studied data from over 6,700 families relating to 45 childhood characteristics, from IQ and hyperactivity through to height and weight. They found that genetic and environmental contributions to these characteristics vary geographically in the United Kingdom, and published their results online as a series of nature-nurture maps.
Our development, health and behaviour are determined by complex interactions between our genetic make-up and the environment in which we live. For example, we may carry genes that increase our risk of developing type 2 diabetes, but if we eat a healthy diet and get sufficient exercise, we may not develop the disease. Similarly, someone may carry genes that reduce his or her risk of developing lung cancer, but heavy smoking may still lead to the disease….
By John Rennie | November 29, 2011, 3:00 AM PST
The era of personal genomics is fast approaching, as headlines constantly remind us. With the cost of sequencing someone’s DNA rapidly falling toward just $1,000 (or less), it seems all but inevitable that soon we and our physicians will use that information to guide our health decisions.
But here’s an inconvenient biological truth that the triumphant talk about personal genomics sometimes skirts: we don’t each have just one genome. Yes, one may stand out most prominently for each of us, but we have others. And biology is still sorting out how much our health may depend on learning to pay attention to those we normally overlook.
All the cells in an organism like a human being certainly seem as though they should have the same genome. A fertilized egg divides repeatedly to give rise to the body’s cells, passing along the same set of chromosomes to every one of its cellular progeny. A few exceptional tissues might deviate from that rule — for example, red blood cells entirely discard the nucleus holding their genes, and the white blood cells called B lymphocytes scramble part of their DNA so that they can make an almost infinite number of different antibodies. But fundamentally, all the cells in the skin, the liver, the brain, the muscles and other tissues ought to share the same genome.
Or so it was thought. Yet exceptions to the rule keep cropping up, and they may help to explain some of the variation seen in tissues like the brain.
Variation on the brain
The hundred billion neurons in the human brain obviously differ from one another in their interconnections and in the specific neurochemical messenger molecules that they secrete. But a more subtle difference that has come to light over the past decade, largely thanks to the work of Michael J. McConnell and his colleagues at the Salk Institute for Biological Studies in La Jolla, Calif., resides in the DNA. They have shown extensive variation in the genomes of individual neurons, a condition called aneuploidy. The neurons have deleted, duplicated, and rearranged portions of their chromosomes, such that no two have exactly the same DNA sequence anymore…..
- Personalized Medicine – Scientific & Commercial Aspects (prnewswire.com)
- Molecular Diagnostics – Technologies, Markets and Companies (prnewswire.com)
- New research brings personal genomics closer than ever (digitaltrends.com)
Mount Sinai researchers develop new gene therapy for heart failure & related general gene therapy Web sites and resources
Researchers at Mount Sinai School of Medicine have found in a Phase II trial that a gene therapy developed at Mount Sinai stabilized or improved cardiac function in people with severe heart failure. Patients receiving a high dose of the therapy, called SERCA2a, experienced substantial clinical benefit and significantly reduced cardiovascular hospitalizations, addressing a critical unmet need in this population. The data are published online in the June 27 issue of the American Heart Association journal Circulation.
SERCA2a is delivered via an adeno-associated virus vector—an inactive virus that acts as a medication transporter—into cardiac cells. The therapy stimulates production of an enzyme within these cells that enables the heart to pump more effectively in people with advanced heart failure. After one year, patients who were administered a high dose SERCA2a demonstrated improvement or stabilization. Gene therapy with SERCA2a was also found to be safe in this sick patient population, with no increases in adverse events, disease-related events, laboratory abnormalities, or arrhythmias compared to placebo….
A sampling of general gene therapy resources
- Genes and gene therapy (MedlinePlus) has links to overviews, latest news, specific conditions, organizations, directories, and more
- Genetics home reference (US National Institutes of Health) with links to information on over 600 conditions/diseases, information on over 600 genes, a handbook with basic gene related information, a glossary, and links to additional resources
- Genetics education center (University of Kansas) with links to education resources, Human Genome Project materials, activities, and more
- Learn Gentics (University of Utah) includes basic information and research related concepts. Extensive animations and videos.
- New gene therapy fixes mistakes (sciencenews.org)
- Genome Editing Improves Blood Clotting in Mice with Hemophilia B (nextbigfuture.com)
- Advances in delivery of therapeutic genes to treat brain tumors (medicalxpress.com)
New Computational Tool For Rapid Identification Of Disease-Causing Variations In The Human Genome & Guides to Genomics Resources
Scientists from the University of Utah and Omicia, Inc., a privately held company developing tools to interpret personal genome sequences, have announced the publication in Genome Research of a new software tool called VAAST, the Variant Annotation, Analysis and Selection Tool, a probabilistic disease-causing mutation finder for individual human genomes.
The dramatic decline in DNA sequencing costs is making personal genome sequencing a reality. Already, significant progress has been made in applying whole genome sequencing to cancerprognosis and early childhood disease. Examples include the 2010 publications on Miller Syndrome in Nature Genetics and Science, and similar studies aimed at identifying the unknown genetic defects responsible for some early childhood diseases…
…However, a data interpretation bottleneck has limited the utility of personal genome information for medical diagnosis and preventive care. VAAST is a new algorithm to assist in overcoming this bottleneck. VAAST is the product of a collaboration between Mark Yandell, Ph.D., Associate Professor of Human Genetics at the University of Utah School of Medicine, and colleagues, and the Omicia scientific team under the leadership of Martin Reese, Ph.D., the company’s CEO and Chief Scientific Officer.
In the Genome Research paper, Yandell and colleagues show that VAAST provides a highly accurate, statistically robust means to rapidly search personal genomes for genes with disease-causing mutations. The authors demonstrate that as few as three genomes from unrelated children, or those of the parents and their two children, are sufficient to identify disease causing mutations.
“The big challenge in genomic medicine today is how to sift through the millions of variants in a personal genome sequence to identify the disease-relevant variations,” said Dr. Reese. “It’s a classic needle in a haystack problem, and VAAST goes a long way toward solving it. We look forward to integrating VAAST into the Omicia Genome Analysis System currently under development for clinical applications.”
Dr. Yandell added: “VAAST solves many of the practical and theoretical problems that currently plague mutation hunts using personal genome sequences. Our results demonstrate that this tool substantially improves upon existing methods with regard to statistical power, flexibility, and scope of use. Further, VAAST is automated, fast, works across all variant population frequencies and is sequencing platform independent.”
Two General Genomics Resources
- Public Health Genomics (US Centers for Disease Control and Prevention) information includes
- Family Health History with collection tools (as how to create a family health portrait), FAQs, fact sheets, and more
- Genetic Testing with information on the limitations for most genetic tests, FAQs, and more
- Links to Genomics Resources, including Disease and Genetic Information, Educational Materials, Genetic Testing, and Support Groups
- Genetics Home Reference – Your Guide to Understanding Genetic Conditions with information on diseases and conditions, information on specific genes, a handbook presenting basic information about genetics in clear language and links to online resources, and more
- “When People Share their Genome on Facebook” (spittoon.23andme.com)
- Genome editing — a next step in genetic therapy — corrects hemophilia in animals (sciencedaily.com)
- Genome Study Solves Twins’ Mystery Illness (nlm.nih.gov)
- Genomics and social network analysis team up to solve disease outbreaks (eurekalert.org)
- Personal genome map solves Calif. teen’s illness (seattletimes.nwsource.com)
- Further Analysis on Improved Genome Assembly Indicates the Outbreak E. coli has Complex Genetics With Resistance to at Least Eight Antibiotics (prnewswire.com)
- Alzheimer’s may cause global cash crunch: experts (physorg.com)
- iPad App Genome Wowser Lets You Browse the Human Genome (news.dice.com)
- Genome sequence could reveal ‘Achilles’ heels’ of important wheat disease (physorg.com)
- We are all mutants (eurekalert.org)
- Now, browse the human genome with iPad app! (news.bioscholar.com)
- Blog – Human Genome Contaminated With Mycoplasma DNA (technologyreview.com)
- Complete Genomics Makes 29 Genomes Public (xconomy.com)
- Decoding human genes is the goal of a new open-source encyclopedia (eurekalert.org)
- Basques (?) in 1000 Genomes IBS (Iberian Spanish) sample (dienekes.blogspot.com)
- Genomics and social network analysis team up to solve disease outbreaks (medicalxpress.com)
The Counterbalance Interactive Library*** offers new views on complex issues from science, ethics, philosophy, and religion. Here you’ll find extensive resources on the evolution/creation controversy, biomedical ethical challenges, and much more.
A sampling of health and medical related topic sets
From the About page
About Counterbalance Foundation
Counterbalance is a non-profit educational organization working to promote counterbalanced perspectives on complex issues. It is our hope that individuals, the academic community, and society as a whole will benefit from a struggle toward integrated and counterbalanced views.
Counterbalance provides design, consulting, and technical services. It is our intention to use our considerable experience in these areas to serve as a catalyst by.
- Helping make existing multidisciplinary research work accessible to a wider audience, principally though the use of interactive technologies.
- Helping collaboration within, and among research groups by providing on-line technology services, such as the shared Meta-Library andAutoReference tools.
Our services are used by PBS Online, The Center for Theology and the Natural Sciences, the AAAS, Science and Religion Forum (UK), and others.
Counterbalance is funded by donations and the Adrian M. Wyard Charitable Trust.
- Ethics of Stem Cell Research: i (somescientistsbelieve.wordpress.com)
- Ethics Education Library | Ethics education resources in engineering & the sciences (ethics.iit.edu)
ScienceDaily (Mar. 20, 2011) — A team of scientists from the University of Oxford, U.K. have taken lessons from Adam Smith and Charles Darwin to devise a new strategy that could one day slow, possibly even prevent, the spread of drug-resistant bacteria. In a new research report published in the March 2011 issue of Genetics, [Abstract***]the scientists show that bacterial gene mutations that lead to drug resistance come at a biological cost not borne by nonresistant strains. They speculate that by altering the bacterial environment in such a way to make these costs too great to bear, drug-resistant strains would eventually be unable to compete with their nonresistant neighbors and die off.“Bacteria have evolved resistance to every major class of antibiotics, and new antibiotics are being developed very slowly; prolonging the effectiveness of existing drugs is therefore crucial for our ability to treat infections,” said Alex Hall, Ph.D., a researcher involved in the work from the Department of Zoology at the University of Oxford. “Our study shows that concepts and tools from evolutionary biology and genetics can give us a boost in this area by identifying novel ways to control the spread of resistance.”
The research team measured the growth rates of resistant and susceptible Pseudomonas aeruginosa bacteria in a wide range of laboratory conditions. They found that the cost of antibiotic resistance has a cost to bacteria, and can be eliminated by adding chemical inhibitors of the enzyme responsible for resistance to the drug. Leveling the playing field increased the ability of resistant bacteria to compete effectively against sensitive strains in the absence of antibiotics. Given that the cost of drug resistance plays an important role in preventing the spread of resistant bacteria, manipulating the cost of resistance may make it possible to prevent resistant bacteria from persisting after the conclusion of antibiotic treatment. For instance, new additives or treatments could render antibiotic resistance more costly for bacteria, making it less likely that the resistant strains will persist at the end of treatment.
“If we’ve learned one thing about microscopic organisms over the past century, it’s that they evolve quickly, and that we can’t stop the process,” said Mark Johnston, Editor-in-Chief of the journal GENETICS. “This research turns this fact against the bacteria. This is an entirely new strategy for extending the useful life of antibiotics, and possibly for improving the potency of old ones.”
- Antibiotic resistance is not just genetic (sciencedaily.com)
- Pollution with antibiotics leads to resistant bacteria (physorg.com)
- Hospital infections: Unique antibody from llamas provide weapon against Clostridium difficile (ScienceDaily [news article])
Scitable is a free science library and personal learning tool by Nature Publishing Group, a science publishing company.
A sampling of topics
- Genes and Diseases
- Genetics and Society (ethical, legal, and social implications (ELSI) of genetic advances and their applications.)
- Gene Inheritance and Transmission
Genes linked to the immune system can affect healthy people’s personality traits as well as the risk of developing mental illness and suicidal behaviour, reveals a thesis from the University of Gothenburg, Sweden.
Inflammation is part of the immune system and is responsible for defending humans against infection as well as fascilitating the healing of injuries, and is therefore vital for our survival. Research has demonstrated that inflammatory processes also have other roles to play as inflammatory substances produced by the body influence mechanisms in the brain involving learning and memory.
Inflammatory substances produced in moderate quantities in the brain can be beneficial during the formation of new brain cells, for example. However, an increase in the levels of these substances as is the case during illness, can result in damage to the brain.
“Previous studies have shown that individuals suffering from various mental illnesses have an increased peripheral inflammation, but the reason behind this increase is not known,” says Petra Suchankova Karlsson, who wrote the thesis. “It has been suggested that the stress that goes with mental illness activates the body’s immune system, but it is also possible that inflammation in the body affects the brain, which in turn results in mental illness.”
Previous studies have focused on how environmental and psychological factors affect the immune system’s impact on the brain. Suchankova’s thesis presents, for the first time, results that suggest that several different genes linked to the immune system are associated with healthy people’s personality traits. It also demonstrates that some of these genes are associated with an increased risk of developing schizophrenia or suicidal behaviour….
This item helps explain why a healthy and prosperous community/society needs a firm foundation on healthy child development. This firm foundation has many genetic and environmental components.
(This blog item/Web page includes a great 7 minute video ,Foundations of Living Health, which outlines how various genetic and environmental factors affect the wellness of both individuals and the society at large)
When we talk about health and healthy living, there seems to be, at times, a division within healthcare (and outside of it) about what are the factors that contribute to your health and wellbeing. Good genes? How well you eat? Whether have a safe neighbourhood to play in? If you take a look at our page on health determinants, you’ll see that all of these, and others, have a role.
Fellow triPop member Sarah Hergett shared the video …[ (at http://www.changingourpictureofhealth.ca/?p=225) ] … with our group the other day, and it’s worth passing on. It’s a presentation from the Center on the Developing Child at Harvard University. In this seven minute presentation, you’ll find how researches from the fields of neuroscience, biology, and public health present the tangible links between what goes on inside our bodies to how that’s impacted on our health throughout our lives. As a librarian – and an advocate for literacy and health literacy – I was particularly thrilled to see libraries on the list of important resources that contribute to our health. So…support your local library! Support your community. It’s good for your health:).
This quoted blog item/Web page includes a great 7 minute video, Foundations of Living Health, which outlines how various genetic and environmental factors affect the wellness of both individuals and the society at large.
This video summarizes findings from The Foundations of Lifelong Health Are Built in Early Childhood, a report co-authored by the National Scientific Council on the Developing Child and the National Forum on Early Childhood Policy and Programs.
The seemingly disparate health/well being factors include undue emotional stress, consumer products readily available (as liquor, fresh produce), healthy social relationships, parenting, individual genetic make-up, physical environments (think lead, tobacco products), schooling, libraries, government agency policies (as WIC), and employee policies affecting parents and others close to the child.
DURHAM, N.C. – Despite what you might have heard, genetic sequencing alone is not enough to understand human disease. Researchers at Duke University Medical Center have shown that functional tests are absolutely necessary to understand the biological relevance of the results of sequencing studies as they relate to disease, using a suite of diseases known as the ciliopathies which can cause patients to have many different traits.
“Right now the paradigm is to sequence a number of patients and see what may be there in terms of variants,” said Nicholas Katsanis, Ph.D. “The key finding of this study says that this approach is important, but not sufficient. If you really want to be able to penetrate, you must have a robust way to test the functional relevance of mutations you find in patients. For a person at risk of type 2 diabetes, schizophrenia or atherosclerosis, getting their genome sequenced is not enough – you have to functionally interpret the data to get a sense of what might happen to the particular patient.”
“This is the message to people doing medical genomics,” said lead author Erica Davis, Ph.D., Assistant Professor in the Duke Department of Pediatrics, who works in the Duke Center for Human Disease Modeling. “We have to know the extent to which gene variants in question are detrimental – how do they affect individual cells or organs and what is the result on human development or disease? Every patient has his or her own set of genetic variants, and most of these will not be found at sufficient frequency in the general population so that anyone could make a clear medical statement about their case.”
Davis, working in the lab of Katsanis, and in collaboration with many ciliopathy labs worldwide, sequenced a gene, TTC21B, known to be a critical component of the primary cilium, an antenna-like projection critical to cell function.
While a few of the mutations could readily be shown to cause two main human disorders, a kidney disease and an asphyxiating thoracic condition, the significance of the majority of DNA variants could not be determined. Davis then tested these variants in a zebrafish model, in which many genes are similar to humans, and showed that TTC21B appears to contribute disease-related mutations to about 5 percent of human ciliopathy cases.
The study, which appears in Nature Genetics online on Jan. 23, shows how genetic variations both can cause ciliopathies and also interact with other disease-causing genes to yield very different sets of patient problems.
Katsanis, the Jean and George Brumley Jr., M.D., Professor of Pediatrics and Cell Biology, and Director of the Duke Center for Human Disease Modeling, is a world expert in ciliopathies such as Bardet-Biedl Syndrome, in which the primary cilium of cells is abnormal and leads to a host of problems. About one child in 1,000 live births will have a ciliopathy, an incidence that is in the range of Down’s syndrome, said Katsanis.
“By sequencing genes to identify genetic variation, followed by functional studies with a good experimental model, we can get a much better idea of the architecture of complex, inherited disorders,” Katsanis said. “Each individual with a disease is unique,” Davis said. “If you can overlay gene sequencing with functional information, then you will be able to increase the fidelity of your findings and it will become more meaningful for patients and families.”
It will take more laboratories doing more pointed studies like this one to get a fuller picture of the ciliopathies and other diseases, Davis said.
Katsanis noted that it will take true collaboration within many scientific disciplines as well as scientific finesse to get at the true roots of complex diseases.
“Brute force alone – sequencing – will not help,” he said. “Technology is of finite resolution. You must have synthesis of physiology, cell biology, biochemistry and other fields to get true penetration into medically relevant information.”
WASHINGTON, Jan. 15, 2011 — In research described as “a stark warning” to those tempted to start smoking, scientists are reporting that cigarette smoke begins to cause genetic damage within minutes — not years — after inhalation into the lungs.
Their report, the first human study to detail the way certain substances in tobacco cause DNA damage linked to cancer, appears in Chemical Research in Toxicology***, one of 38 peer-reviewed scientific journals published by the American Chemical Society.
Stephen S. Hecht, Ph.D., and colleagues point out in the report that lung cancer claims a global toll of 3,000 lives each day, largely as a result of cigarette smoking. Smoking also is linked to at least 18 other types of cancer. Evidence indicates that harmful substances in tobacco smoke termed polycyclic aromatic hydrocarbons, or PAHs, are one of the culprits in causing lung cancer. Until now, however, scientists had not detailed the specific way in which the PAHs in cigarette smoke cause DNA damage in humans.
The scientists added a labeled PAH, phenanthrene, to cigarettes and tracked its fate in 12 volunteers who smoked the cigarettes. They found that phenanthrene quickly forms a toxic substance in the blood known to trash DNA, causing mutations that can cause cancer. The smokers developed maximum levels of the substance in a time frame that surprised even the researchers: Just 15-30 minutes after the volunteers finished smoking. Researchers said the effect is so fast that it’s equivalent to injecting the substance directly into the bloodstream.
“This study is unique,” writes Hecht, an internationally recognized expert on cancer-causing substances found in cigarette smoke and smokeless tobacco. “It is the first to investigate human metabolism of a PAH specifically delivered by inhalation in cigarette smoke, without interference by other sources of exposure such as air pollution or the diet. The results reported here should serve as a stark warning to those who are considering starting to smoke cigarettes,” the article notes.
Poverty May Keep Kids From Full Genetic Potential
Study finds disparities between rich, poor show up by age 2
MONDAY, Jan. 17 (HealthDay News) — Being poor can prevent young children from reaching their full genetic potential of mental ability, a new study shows.
Researchers at the University of Texas at Austin looked at 750 sets of twins who took a test of cognitive ability at ages 10 months and 2 years. During the tests the children were asked to perform such tasks as pulling a string to ring a bell, placing three cubes in a cup, and matching pictures.
At 10 months, children from all socioeconomic backgrounds performed the same on the test. But by 2 years, children from richer families scored significantly higher than those from poorer families, the investigators found.
The study results, published in the January issue of the journal
, don’t suggest that children from wealthier families are genetically superior or smarter. These children simply have more opportunity to reach their potential, explained study author Elliott Tucker-Drob, an assistant professor of psychology, in a university news release.
These findings indicate that “nature” and “nurture” work together to affect a child’s development and that the right environment can help children begin to reach their genetic potential at a much younger age than previously thought, he added.
“You can’t have environmental contributions to a child’s development without genetics. And you can’t have genetic contributions without environment. Socioeconomic disadvantages suppress children’s genetic potentials,” Tucker-Drob said.
SOURCE: University of Texas at Austin, news release, Jan. 10, 2011
Personalized medicine centers on being able to predict the risk of disease or response to a drug based on a person’s genetic makeup. But a study by scientists at Washington University School of Medicine in St. Louis suggests that, for most common diseases, genes alone only tell part of the story.
That’s because the environment interacts with DNA in ways that are difficult to predict, even in simple organisms like single-celled yeast, their research shows.
“The effects of a person’s genes – and, therefore, their risk of disease – are greatly influenced by their environment,” says senior author Barak Cohen, PhD, a geneticist at Washington University School of Medicine. “So, if personalized medicine is going to work, we need to find a way to measure a human’s environment.”
The new research raises many questions: what is a human’s environment and how can it be measured? Is the environment a person lived in during childhood important or the environment he lives in now?
Cohen suspects that any environment that matters is likely to leave a measurable molecular signature. For example, eating a lot of fatty foods raises triglycerides; smoking raises nicotine levels; and eating high-fat, high-sugar foods raises blood sugar levels, which increases the risk of diabetes. The key, he says, is to figure out what are good metabolic readouts of the environment and factor those into statistical models that assess genetic susceptibility to disease or response to medication.
“Measuring the environment becomes crucial when we try to understand how it interacts with genetics,” Cohen says. “Having a particular genetic variant may not have much of an effect but combined with a person’s environment, it may have a huge effect.”
Cohen says he’s not hopeless when it comes to personalized medicine. As scientists conduct ever-larger studies to identify rare and common variants underlying diseases such as cancer, diabetes and schizophrenia, they will be more likely to uncover variants that have larger effects on disease. Even then, however, a person’s environment will be important, he adds.
BETHESDA, MD – October 22, 2010 – Thousands of the world’s top scientists and clinicians in the human genetics field will convene to present their latest research findings at the American Society of Human Genetics 60th Annual Meeting, which will be held November 2-6, 2010, in Washington, D.C.
A number of scientific presentations at this year’s meeting will feature research on the application and use of family health history information in clinical settings to assess an individual’s risk for developing common chronic diseases. Family health history assessment is an inexpensive, simple, and useful tool that has been shown to be effective and accurate when implemented in clinical care settings to assess personal disease risks. Integrating the use of family health history information in clinical practice can help practitioners determine which patients are at high risk of developing a specific health condition and would benefit from taking precautionary measures to prevent disease (such as early and frequent screening, genetic testing, health behavior and lifestyle changes, etc.)…….
…Since National Family Health History Month is celebrated in November, ASHG will be spreading awareness about this important public health topic and helping people understand its application in clinical practice as a cost-effective tool for assessing disease risk by hosting a press briefing to highlight some of the latest research findings of interest on this topic that will be presented at the ASHG 2010 Annual Meeting.
Some Family Health History Tools
- My Family Health Portrait (US Surgeon General Office)
Using My Family Health Portrait you can:
- Enter your family health history.
- Print your family health history to share with family or your health care worker.
- Save your family health history so you can update it over time.
- Family Healthware (US Centers for Disease Control and Prevention
[currently in development]
The Web site Genetic Testing includes the following
- Overview of Genetic Testing , with a link to A Brief Primer on Genetic Testing (a summary of current genetic testing)
- The Growth of Genetic Testing Raises Questions
- Legislation on Genetic Testing
- NHGRI Interest in Genetic Testing, including its concerns (as genetic discrimination) and activities (as providing information for genetic counselors)
- Policy Recommendations
- (Links to) Reports on Genetic Testing from government and nonprofit agencies
**[ From About the Insitute ]NHGRI’s initial mission was to map the human genome. Its role has been expanded to include applying genome technologies to the study of specific diseases and study the genetic components of complex disorders. Its human genome sequence database is available to scientists worldwide.
The NHGRI Web site includes information about
- NHGRI research
- Information about genetics and genomics, rare diseases, patient care and more (for patients, the public, and health professionals)
- Educational materials about genetics and genomics for students and teachers
- Policy, legal and ethical issues in genetic research
- Latest news, media resources and information from NHGRI
- Education, training, professional development and career opportunities at NHGRI
- (Under the For You tab)
Specialized information for Students, Educators, Patients, Health Professionals
THURSDAY, Oct. 7 (HealthDay News) — Do your genes predispose you to thrill-seeking?
Scientists looking into this question have found a dozen gene mutations associated with the urge to do exciting things.
This urge, called “sensation seeking” by researchers, has been linked to the neurotransmitter dopamine, a chemical that carries messages in the brain. In research that involved 635 people enrolled in a study on addiction, the scientists looked at 273 genetic mutations — involving a change in just one letter of the DNA — known to occur in eight genes with roles related to dopamine.
That number was eventually narrowed down to a dozen potentially important mutations. When those 12 gene variants were combined, they explained just under 4 percent of the difference between people who are sensation seekers and those who are not. This may not seem like much but it is “quite large for a genetic study,” according to study first author Jaime Derringer, a doctoral student at the University of Minnesota.
However, she added, it’s too early to start screening people for these mutations because not enough is known about how genes affect behavior.
While sensation seeking has been linked to a range of behavior disorders, such as drug addiction, it can be a positive trait.
“Not everyone who’s high on sensation-seeking becomes a drug addict. They may become an Army Ranger or an artist. It’s all in how you channel it,” Derringer said.
The study appears in the current issue of the journal Psychological Science.
“Transposons are sequences in the DNA code that can replicate themselves. They “jump” from one place to another on the chromosomes. Devine’s team found unique transposons in more than 90 percent of the 76 people they studied, they reported in the journal Cell.
These mutations can affect the functions of other genes. Stretches of DNA right in front of or behind a gene can turn it on, turn it off, or affect the way it functions.
That people have transposons is not new. “Forty-five percent of the genome is known to be transposon sequences,” Devine said. But most hopped in and are now inactive, passing down unchanged and in place from one generation to the next.
“What we are interested in are the ones that are moving around today. We found an average of 15 new insertions per person,” Devine said in a telephone interview.”
News item may be found here.