Scientists discover how epigenetic information could be inherited

Research reveals the mechanism of epigenetic reprogramming

2013-01-25

(Press-News.org) New research reveals a potential way for how parents' experiences could be passed to their offspring's genes. The research was published today, 25 January, in the journal Science.

Epigenetics is a system that turns our genes on and off. The process works by chemical tags, known as epigenetic marks, attaching to DNA and telling a cell to either use or ignore a particular gene.

The most common epigenetic mark is a methyl group. When these groups fasten to DNA through a process called methylation they block the attachment of proteins which normally turn the genes on. As a result, the gene is turned off.

Scientists have witnessed epigenetic inheritance, the observation that offspring may inherit altered traits due to their parents' past experiences. For example, historical incidences of famine have resulted in health effects on the children and grandchildren of individuals who had restricted diets, possibly because of inheritance of altered epigenetic marks caused by a restricted diet.

However, it is thought that between each generation the epigenetic marks are erased in cells called primordial gene cells (PGC), the precursors to sperm and eggs. This 'reprogramming' allows all genes to be read afresh for each new person - leaving scientists to question how epigenetic inheritance could occur.

The new Cambridge study initially discovered how the DNA methylation marks are erased in PGCs, a question that has been under intense investigation over the past 10 years. The methylation marks are converted to hydroxymethylation which is then progressively diluted out as the cells divide. This process turns out to be remarkably efficient and seems to reset the genes for each new generation. Understanding the mechanism of epigenetic resetting could be exploited to deal with adult diseases linked with an accumulation of aberrant epigenetic marks, such as cancers, or in 'rejuvenating' aged cells.

However, the researchers, who were funded by the Wellcome Trust, also found that some rare methylation can 'escape' the reprogramming process and can thus be passed on to offspring – revealing how epigenetic inheritance could occur. This is important because aberrant methylation could accumulate at genes during a lifetime in response to environmental factors, such as chemical exposure or nutrition, and can cause abnormal use of genes, leading to disease. If these marks are then inherited by offspring, their genes could also be affected.

Dr Jamie Hackett from the University of Cambridge, who led the research, said: "Our research demonstrates how genes could retain some memory of their past experiences, revealing that one of the big barriers to the theory of epigenetic inheritance - that epigenetic information is erased between generations - should be reassessed."

"It seems that while the precursors to sperm and eggs are very effective in erasing most methylation marks, they are fallible and at a low frequency may allow some epigenetic information to be transmitted to subsequent generations. The inheritance of differential epigenetic information could potentially contribute to altered traits or disease susceptibility in offspring and future descendants."

"However, it is not yet clear what consequences, if any, epigenetic inheritance might have in humans. Further studies should give us a clearer understanding of the extent to which heritable traits can be derived from epigenetic inheritance, and not just from genes. That could have profound consequences for future generations."

Professor Azim Surani from the University of Cambridge, principal investigator of the research, said: "The new study has the potential to be exploited in two distinct ways. First, the work could provide information on how to erase aberrant epigenetic marks that may underlie some diseases in adults. Second, the study provides opportunities to address whether germ cells can acquire new epigenetic marks through environmental or dietary influences on parents that may evade erasure and be transmitted to subsequent generations, with potentially undesirable consequences."

### For additional information please contact: Genevieve Maul, Office of Communications, University of Cambridge
Tel: direct, +44 (0) 1223 765542, +44 (0) 1223 332300
Mob: +44 (0) 7774 017464
Email: Genevieve.maul@admin.cam.ac.uk

Notes to editors:

1. The paper 'Germline DNA Demethylation Dynamics and Imprint Erasure Through 5-Hydroxymethylcytosine' will be published in the 25 January 2013 edition of Science.

2. The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust's breadth of support includes public engagement, education and the application of research to improve health. It is independent of both political and commercial interests. www.wellcome.ac.uk

ELSE PRESS RELEASES FROM THIS DATE:

Researchers discover new mutations driving malignant melanoma

2013-01-25

BOSTON—Two new mutations that collectively occur in 71 percent of malignant melanoma tumors have been discovered in what scientists call the "dark matter" of the cancer genome, where cancer-related mutations haven't been previously found. Reporting their findings in the Jan. 24 issue of Science Express, the researchers from Dana-Farber Cancer Institute and the Broad Institute said the highly "recurrent" mutations – occurring in the tumors of many people – may be the most common mutations in melanoma cells found to date. The researchers said these cancer-associated ...

Red explosions: The secret life of binary stars is revealed

2013-01-25

(Edmonton) A University of Alberta professor has revealed the workings of a celestial event involving binary stars that results in an explosion so powerful it ranks close to Supernovae in luminosity. Astrophysicists have long debated about what happens when binary stars, two stars that orbit one another, come together in a common envelope. When this dramatic cannibalizing event ends there are two possible outcomes; the two stars merge into a single star or an initial binary transforms in an exotic short-period one. The event is believed to take anywhere from a dozen ...

Gene sequencing project mines data once considered 'junk' for clues about cancer

2013-01-25

(MEMPHIS, Tenn. – January 24, 2013) Genome sequencing data once regarded as junk is now being used to gain important clues to help understand disease. The latest example comes from the St. Jude Children's Research Hospital – Washington University Pediatric Cancer Genome Project, where scientists have developed an approach to mine the repetitive segments of DNA at the ends of chromosomes for insights into cancer. These segments, known as telomeres, had previously been ignored in next-generation sequencing efforts. That is because their repetitive nature meant that the ...

Newly discovered 'scarecrow' gene might trigger big boost in food production

2013-01-25

ITHACA, N.Y. – With projections of 9.5 billion people by 2050, humanity faces the challenge of feeding modern diets to additional mouths while using the same amounts of water, fertilizer and arable land as today. Cornell University researchers have taken a leap toward meeting those needs by discovering a gene that could lead to new varieties of staple crops with 50 percent higher yields. The gene, called Scarecrow, is the first discovered to control a special leaf structure, known as Kranz anatomy, which leads to more efficient photosynthesis. Plants photosynthesize ...

The storm that never was: Why the weatherman is often wrong

2013-01-25

Have you ever woken up to a sunny forecast only to get soaked on your way to the office? On days like that it's easy to blame the weatherman. But BYU mechanical engineering professor Julie Crockett doesn't get mad at meteorologists. She understands something that very few people know: it's not the weatherman's fault he's wrong so often. According to Crockett, forecasters make mistakes because the models they use for predicting weather can't accurately track highly influential elements called internal waves. Atmospheric internal waves are waves that propagate between ...

Prenatal inflammation linked to autism risk

2013-01-25

Maternal inflammation during early pregnancy may be related to an increased risk of autism in children, according to new findings supported by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health. Researchers found this in children of mothers with elevated C-reactive protein (CRP), a well-established marker of systemic inflammation. The risk of autism among children in the study was increased by 43 percent among mothers with CRP levels in the top 20th percentile, and by 80 percent for maternal CRP in the top 10th ...

Virginia Tech computer scientists develop new way to study molecular networks

2013-01-25

In biology, molecules can have multi-way interactions within cells, and until recently, computational analysis of these links has been "incomplete," according to T. M. Murali, associate professor of computer science in the College of Engineering at Virginia Tech. His group authored an article on their new approach to address these shortcomings, titled "Reverse Engineering Molecular Hypergraphs," that received the Best Paper Award at the recent 2012 ACM Conference on Bioinformatics, Computational Biology and Biomedicine. Intricate networks of connections among molecules ...

'Cool' kids in middle school bully more, UCLA psychologists report

2013-01-25

Bullying, whether it's physical aggression or spreading rumors, boosts the social status and popularity of middle school students, according to a new UCLA psychology study that has implications for programs aimed at combatting school bullying. In addition, students already considered popular engage in these forms of bullying, the researchers found. The psychologists studied 1,895 ethnically diverse students from 99 classes at 11 Los Angeles middle schools. They conducted surveys at three points: during the spring of seventh grade, the fall of eighth grade and the spring ...

A blend of soy and dairy proteins promotes muscle protein synthesis when consumed after exercise

2013-01-25

ST. LOUIS, Jan. 24, 2013 – A new study published in The Journal of Nutrition demonstrates the benefits of consuming a protein blend for muscle protein synthesis after exercise. This study is a first-of-its-kind, conducted by researchers at the University of Texas Medical Branch, and utilizes the proteins from soy, whey and casein consumed after an acute bout of resistance exercise. These proteins have complementary amino acid profiles and different digestion rates (amino acid release profiles). The results demonstrate prolonged delivery of amino acids to muscles and ...

Genes provide clues to gender disparity in human hearts

2013-01-25

Healthy men and women show little difference in their hearts, except for small electrocardiographic disparities. But new genetic differences found by Washington University in St. Louis researchers in hearts with disease could ultimately lead to personalized treatment of various heart ailments. Generally, men are more susceptible to developing atrial fibrillation, an irregular, rapid heartbeat that may lead to stroke, while women are more likely to develop long-QT syndrome, a rhythm disorder that can cause rapid heartbeats and sudden cardiac death. While prior studies ...

Scientists discover how epigenetic information could be inherited

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: