Finding our genomic clockwork

first_img In pursuit of healthy aging Critical step found in DNA repair, cellular aging Experiments in mice suggest way to thwart DNA damage from aging, radiation Related Harvard study shows how intermittent fasting and manipulating mitochondrial networks may increase lifespan For this new study, the researchers looked at the rDNA, the most active segment of the genome and one that has also been mechanistically linked to aging in a number of previous studies. Lemos and lead author Meng Wang, a research fellow in the Department of Environmental Health, hypothesized that the rDNA is a “smoking gun” in the genomic control of aging, and might harbor a previously unrecognized clock. To test the idea, they examined epigenetic chemical alterations (also known as DNA methylation) in CpG sites, where a cytosine nucleotide is followed by a guanine nucleotide. The study homed in on the rDNA, a small (13-kilobase) but essential and highly active segment of the genome, as a novel marker of age.Analysis of genome-wide data sets from mice, dogs, and humans indicated that the hypothesis had merit: Numerous CpGs in the rDNA exhibited signs of increased methylation — a result of aging. To further test the clock, they studied data from 14-week-old mice that responded to calorie restriction, a known intervention that promotes longevity. The mice that were placed on a calorie-restricted regimen showed significant reductions in rDNA methylation at CpG sites compared with mice that did not have their diet restricted. Moreover, calorie-restricted mice showed rDNA age that was younger than their chronological age.The researchers were surprised that assessing methylation in a small segment of the mammalian genome yielded clocks as accurate as clocks built from hundreds of thousands of sites along the genome. They noted that their approach could prove faster and more cost-effective at determining biological and chronological age than current methods of surveying the dispersed sites in the genome. The findings underscore the fundamental role of rDNA in aging and highlight its potential as a widely applicable predictor of age that can be calibrated for all mammalian species.Importantly, the clocks respond to interventions, which could allow scientists to study how biological age responds to environmental exposures and lifestyle choices. Ascertaining an accurate biological age can indicate of how much better or worse an individual is doing relative to the general population, and could potentially help monitor whether that person is at heightened risk of death or a given disease. Work in Lemos’ lab has been partially supported by the National Institute of Environmental Health Sciences, the Lawrence Ellison Medical Foundation, and the Richard and Susan Smith Family Foundation, though the authors received no specific funding for this work.  A newly discovered ribosomal DNA (rDNA) clock can be used to accurately determine an individual’s chronological and biological age, according to research led by Harvard T.H. Chan School of Public Health. The ribosomal clock is a novel biomarker of aging based on the rDNA, a segment of the genome that previously has been mechanistically linked to aging. It has potentially wide applications, including measuring how exposures to certain pollutants or dietary interventions accelerate or slow aging in a diversity of species, including mice and humans.“We have hopes that the ribosomal clock will provide new insights into the impact of the environment and personal choices on long-term health,” said senior author Bernardo Lemos, associate professor of environmental epigenetics. “Determining biological age is a central step to understanding fundamental aspects of aging as well as developing tools to inform personal and public health choices.”The study was published online today in Genome Research.Aging is exhibited by organisms as diverse as yeast, worms, flies, mice, and humans. Age is also the major risk factor for a plethora of diseases, including neurological diseases, cardiovascular diseases, and cancer. There are two types of age: chronological age, or the number of years a person or animal has lived, and biological age, which accounts for lifestyle factors that can shorten or extend lifespan, including diet, exercise, and environmental exposures. Overall, biological age has been shown to be a better predictor of all-cause mortality and disease onset than chronological age. Overall, biological age has been shown to be a better predictor of all-cause mortality and disease onset than chronological age.last_img read more

Alpena High School students set expectations for the year during culture week

first_imgAddThis Sharing ButtonsShare to FacebookFacebookShare to TwitterTwitterShare to MoreAddThisALPENA, MICH — Today marks the first day back to school. Students are getting equipped to take on the year with an unconventional concept, making their own rules. Principal of Alpena High School, Tom Berriman says,“”When we were in school, you walk in the first day, [and you’re told] the rules. Well that was top down implementation. They’re telling you what to do. They’re telling you how to respond.”Alpena High School is changing that concept, welcoming students back with a program called culture week. Berriman says,“We don’t want to talk to the kids, we want to talk with the kids. And while we have rules and we have expectations, we want the students to have a voice as well, as to what they believe as well, so then if they violate one of those expectations, they’ve had a say in the creation of it.”Staff at the high school took time over the summer to establish a guide for goals and consequences students should expect of themselves by using school pride as a baseline.“We want to center everything around ‘What is a Wildcat?’ How does a Wildcat behave? A Wildcat has respect, is responsible, has integrity and has grit. And so these are kind of the four things that we’ve centered as the centerpiece of our culture, so that when we say to a student, ‘Are you acting like a Wildcat? are you being a Wildcat?’ they understand what we’re saying.”Berriman says he hopes to carry plans made during culture week into the rest of the school year to produce citizens who will make a difference in the world.“It just kind of goes a long way to producing the type of graduate that when we give them their diploma at the end of their four years, we feel confident that they can go into the work force and be productive members of society.”AddThis Sharing ButtonsShare to FacebookFacebookShare to TwitterTwitterShare to MoreAddThis Tags: Alpena High School, culture week, expectations, SchoolContinue ReadingPrevious Gladwin angler caught with over 1,400 panfishNext Truck destroyed after fire engulfs it early Tuesday morninglast_img read more

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