(Press-News.org) Researchers funded by the Biotechnology and Biological Sciences Research Council (BBSRC) at the John Innes Centre have made a discovery, reported this evening (24 July) in Nature, that explains how an organism can create a biological memory of some variable condition, such as quality of nutrition or temperature. The discovery explains the mechanism of this memory – a sort of biological switch – and how it can also be inherited by offspring.
The work was led by Professor Martin Howard and Professor Caroline Dean at the John Innes Centre, which receives strategic funding from BBSRC. Funding for the project came from BBSRC, the European Research Council, and The Royal Society.
Professor Dean said "There are quite a few examples that we now know of where the activity of genes can be affected in the long term by environmental factors. And in some cases the environment of an individual can actually affect the biology or physiology of their offspring but there is no change to the genome sequence."
For example, some studies have shown that in families where there was a severe food shortage in the grandparents' generation, the children and grandchildren have a greater risk of cardiovascular disease and diabetes, which could be explained by epigenetic memory. But until now there hasn't been a clear mechanism to explain how individuals could develop a "memory" of a variable factor, such as nutrition.
The team used the example of how plants "remember" the length of the cold winter period in order to exquisitely time flowering so that pollination, development, seed dispersal and germination can all happen at the appropriate time.
Professor Howard said "We already knew quite a lot about the genes involved in flowering and it was clear that something goes on in winter that affects the timing of flowering, according to the length of the cold period."
Using a combination of mathematical modelling and experimental analysis the team has uncovered the system by which a key gene called FLC is either completely off or completely on in any one cell and also later in its progeny. They found that the longer the cold period, the higher the proportion of cells that have FLC stably flipped to the off position. This delays flowering and is down to a phenomenon known as epigenetic memory.
Epigenetic memory comes in various guises, but one important form involves histones - the proteins around which DNA is wrapped. Particular chemical modifications can be attached to histones and these modifications can then affect the expression of nearby genes, turning them on or off. These modifications can be inherited by daughter cells, when the cells divide, and if they occur in the cells that form gametes (e.g. sperm in mammals or pollen in plants) then they can also pass on to offspring.
Together with Dr Andrew Angel (also at the John Innes Centre), Professor Howard produced a mathematical model of the FLC system. The model predicted that inside each individual cell, the FLC gene should be either completely activated or completely silenced, with the fraction of cells switching to the silenced state increasing with longer periods of cold.
To provide experimental evidence to back up the model, Dr Jie Song in Prof. Dean's group used a technique where any cell that had the FLC gene switched on, showed up blue under a microscope. From her observations, it was clear that cells were either completely switched or not switched at all, in agreement with the theory.
Dr Song also showed that the histone proteins near the FLC gene were modified during the cold period, in such a way that would account for the switching off of the gene.
Professor Douglas Kell, Chief Executive, BBSRC said "This work not only gives us insight into a phenomenon that is crucial for future food security – the timing of flowering according to climate variation – but it uncovers an important mechanism that is at play right across biology. This is a great example of where the research that BBSRC funds can provide not only a focus on real life problems, but also a grounding in the fundamental tenets of biology that will underpin the future of the field. It also demonstrates the value of multidisciplinary working at the interface between biology, physics and mathematics."
### END
Epigenetic 'memory' key to nature versus nurture
2011-07-25
ELSE PRESS RELEASES FROM THIS DATE:
Soft spheres settle in somewhat surprising structure
2011-07-25
Latex paints and drug suspensions such as insulin or amoxicillin that do not need to be shaken or stirred may be possible thanks to a new understanding of how particles separate in liquids, according to Penn State chemical engineers, who have developed a method for predicting the way colloidal components separate based on energy.
"The ongoing assumption was that if you have a mixture of different sized particles in a liquid, the faster-settling particles will end up on the bottom," said Darrell Velegol, professor of chemical engineering. "We found that in many cases it ...
Mismatch between cancer genetics counseling and testing guidelines and physician practices
2011-07-25
A new analysis has found that many doctors report that they do not appropriately offer breast and ovarian cancer counseling and testing services to their female patients. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study indicates that efforts are needed to encourage these services for high-risk women and discourage them for average-risk women.
Women with mutations in the BRCA1 or BRCA2 gene have a substantially increased risk of developing breast and ovarian cancer, but there are medical treatments that can dramatically ...
Children eating more, and more frequently outside the home
2011-07-25
Philadelphia, PA, July 25, 2011 – As childhood obesity rises and the American diet shifts towards increasing consumption of foods eaten or prepared outside of the home, concerns about the nutritional quality and the total consumption of such foods are also increasing. According to a study conducted at the University of North Carolina at Chapel Hill and published in the August 2011 issue of the Journal of the American Dietetic Association, eating location and food source significantly impact daily energy intake for children. Foods prepared away from home, including fast ...
Catching the West Nile virus in action
2011-07-25
Tel Aviv — Since 1999, several outbreaks of West Nile Virus, which causes fever or severe neurological symptoms and is transmitted from birds to humans by blood-sucking mosquitoes, have been seen in the U.S., usually during the summer months. But researchers aren't certain how the virus migrated here — and they don't know how, or where, it will appear next.
Now Prof. Ella Mendelson of Tel Aviv University's School of Public Health at the Sackler Faculty of Medicine, working with the Israeli Ministries of Health and Environment, has instituted a study that tracks both clinical ...
Double jeopardy: Tuna and billfish
2011-07-25
MIAMI – July 25, 2011 – A new study by top global fisheries experts presents an alarming assessment of several economically important fish populations. The analysis of 61 species of "scombrids," which include tunas, bonitos, mackerels and Spanish mackerels, and billfishes, which include swordfish and marlins, classified seven as threatened with extinction and four as "near threatened" for the IUCN Red List of Threatened Species.
University of Miami Rosenstiel School of Marine & Atmospheric Science associate professor, and assistant director of NOAA's Cooperative Institute ...
Pekasus, Factory of Animated Dreams, Today Announces the Publication of its Newest Book in its Ongoing Series, Spark the Stone Man
2011-07-25
The book's 16 full-color illustrations are the handiwork of British Academy Award recipient and Oscar nominee, Olga Titova. Another key participant in the project is Aida Zyablikova, a movie director and a British Academy Award recipient and Oscar nominee.
Asya Pekurovskaya says there will eventually be six books in the Spark's series. Two have now been published and two more are waiting in the wings. She is currently at work finishing the final two. Each book, she says, stands on its own but also builds upon earlier books and the Spark the Stone Man cosmology. The entire ...
Win Top Technology Prizes with Cake Poker and RakeTheRake
2011-07-25
In celebration of its recent relaunch, RakeTheRake has three superb technology prizes to be won, courtesy of Cake Poker. The promotion is part of a three month period of special relaunch promotions , running until 31 July. Worth $100k+, these promotions are on top of the regular $500k+ of monthly promotions at RakeTheRake.com.
Cake Poker players can play to win one of these great prizes: 1st place will win an X-box and a large screen TV; 2nd place will win a new iPad2 and 3rd place will receive a notebook.
Cake Poker players can enter by checking the rake requirements ...
Triad Alcohol Pads Recalled After Reports of Deadly Bacteria Contamination
2011-07-25
Despite the recall of millions of alcohol wipes, swabs and swabsticks by manufacturer Triad Group, new reports of serious infections and deaths continue. According to the Food and Drug Administration, these alcohol prep pads are used to disinfect the skin prior to an injection, but tests have shown that a large number of the pads are infected with a lethal bacteria Bacillus cereus.
The pads were sold at Walgreens, CVS and countless other drug stores throughout the country. Prior to the recall of the potentially dangerous drug, the pads were also used at hospitals across ...
Number of Partners more than Doubles for Social Media Archiver Arkovi
2011-07-25
BMRW & Associates, Inc., the developers of Arkovi, reported this week that the number of affiliated business partners for the social media archiving service has more than doubled since the beginning of the year.
"We empower our partners to leverage their expertise and relationships with our comprehensive, compliant social media archiving solutions," Blane Warrene, Chief Executive Officer, said recently. Mr. Warrene, along with principals Carl Cline and Tyson Lowery, founded the firm in 2009. Awarded "Best in Tech 2010" by Morningstar Advisor, ...
Running from a Collection Agency After Not Paying Taxes? Instead, Run Right to the Offices of Blue Tax!
2011-07-25
A worst case scenario for a taxpayer who is behind in their payments is a collection agency chasing you down at the behest of the government.
This worst case scenario was Frank's (Madison, GA) real life scenario when he walked into the offices of Blue Tax. Frank owed the State of Georgia just over $10,000 in back taxes. Most of the liability was sent to a third party collection agency. The agency was demanding a $600 a month payment plan!
Nothing gets the Blue Tax team's blood boiling like collection agencies! However, they knew that it would be a challenge to get ...