Quantcast
Connect with us

Scientists unveil map of the ‘epigenome’ — a second genetic code

Published

on

Scientists for the first time have mapped out the molecular “switches” that can turn on or silence individual genes in the DNA in more than 100 types of human cells, an accomplishment that reveals the complexity of genetic information and the challenges of interpreting it.

Researchers unveiled the map of the “epigenome” in the journal Nature on Wednesday, alongside nearly two dozen related papers. The mapping effort is being carried out under a 10-year, $240 million U.S. government research program, the Roadmap Epigenomics Program, which was launched in 2008.

ADVERTISEMENT

The human genome is the blueprint for building an individual person. The epigenome can be thought of as the cross-outs and underlinings of that blueprint: if someone’s genome contains DNA associated with cancer but that DNA is “crossed out” by molecules in the epigenome, for instance, the DNA is unlikely to lead to cancer.

As sequencing individuals’ genomes to infer the risk of disease becomes more common, it will become all the more important to figure out how the epigenome is influencing that risk as well as other aspects of health. Sequencing genomes is the centerpiece of the “precision medicine” initiative that U.S. President Barack Obama announced this month.

“The only way you can deliver on the promise of precision medicine is by including the epigenome,” said Manolis Kellis of the Massachusetts Institute of Technology, who led the mapping that involved scientists in labs from Croatia to Canada and the United States.

Drug makers including Merck & Co Inc., the Genentech unit of Roche Holding and GlaxoSmithKline Plc are conducting epigenetics research related to cancer, said Joseph Costello of the University of California, San Francisco, director of one of four main labs that contributed data to the epigenome map.

ADVERTISEMENT

Epigenetic differences are one reason identical twins, who have identical DNA, do not always develop the same genetic diseases, including cancer.

But incorporating the epigenome in precision medicine is daunting.

“A lifetime of environmental factors and lifestyle factors” influence the epigenome, including smoking, exercising, diet, exposure to toxic chemicals and even parental nurturing, Kellis said in an interview. Not only will scientists have to decipher how the epigenome affects genes, they will also have to determine how the lives people lead affect their epigenome.

ADVERTISEMENT

BOOK OF LIFE

The human genome is the sequence of all the DNA on chromosomes. The DNA is identical in every cell, from neurons to hearts to skin.

It falls to the epigenome to differentiate the cells: as a result of epigenetic marks, heart muscle cells do not make brain chemicals, for instance, and neurons do not make muscle fibers.

ADVERTISEMENT

The epigenome map published on Wednesday shows how each of 127 tissue and cell types differs from every other at the level of DNA. Because scientists involved in the Roadmap project have been depositing their findings in a public database as they went along, other researchers have been analyzing the information before the map was formally published.

One of the resulting studies show, for instance, that brain cells from people who died with Alzheimer’s disease had epigenetic changes in DNA involved in immune response. Alzheimer’s has never been seen as an immune-system disorder, so the discovery opens up another possible avenue to understand and treat it.

Other researchers found that because the epigenetic signature of different kinds of cells is unique, they could predict with nearly 90 percent accuracy where metastatic cancer originated, something that is unknown in 2 percent to 5 percent of patients.

ADVERTISEMENT

As a result, epigenetic information might offer a life-saving clue for oncologists trying to determine treatment, said co-senior author Shamil Sunyaev, a research geneticist at Brigham and Women’s Hospital in Boston.

There is much more to come. Instead of the epigenome map being the end, said Kellis, “I very much see (it) as beginning a decade of epigenomics.”

(Reporting by Sharon Begley; Editing by Michele Gershberg and Lisa Shumaker)


Report typos and corrections to: [email protected].
READ COMMENTS - JOIN THE DISCUSSION
Continue Reading

Breaking Banner

Historians demolish John Yoo for claim Founding Fathers wouldn’t want Trump impeached in an election year

Published

on

Comments made by attorney and law professor John Yoo on Fox News on the Founding Father's intentions about impeachment received a brutal debunking by two historians -- including one of his colleagues at UC Berkeley.

Appearing with Fox News personality Laura Ingraham, lawyer Yoo -- who is infamous for providing President George W. Bush's administration with legal justifications for the torture of prisoners of war -- claimed that the Founding Fathers would object to the president being impeached in an election year.

According to Yoo, Democrats are getting it all wrong when they say the Constitution compels them to hold impeachment proceedings against Trump just one year before the election.

Continue Reading

Breaking Banner

McConnell drops a surprise on Trump — calls for an even stronger resolution to rebuke him

Published

on

Senate Majority Leader Mitch McConnell (R-KY) indicated he opposes the bill out of the House to denounce President Donald Trump's military withdrawal in Syria because it isn't tough enough, reported Bloomberg's Steven Dennis.

https://twitter.com/StevenTDennis/status/1184840222846148608

"My first preference is for something stronger than the House resolution," McConnell said according to Bloomberg's Laura Litvan.

She went on to say that McConnel wants a bill that outlines what action should take place in Syria.

McConnell said the House version was "curiously silent on the issue of whether to actually to sustain a U.S. military presence in Syria."

Continue Reading
 

Facebook

Pelosi asks America to pray for Trump’s health after president suffers a ‘very serious meltdown’

Published

on

President Donald Trump's Twitter attack on House Speaker Nancy Pelosi following an acrimonious White House meeting appears to have backfired spectacularly.

Trump tweeted a picture of the encounter Wednesday showing a standing Pelosi pointing at the president while he and everyone else in the room was seated, with the caption "Nervous Nancy's unhinged meltdown!"

However, far from being upset at the picture, Pelosi posted it as her Twitter banner, and her supporters said it showed her literally standing up to Trump.

"Can a woman beat Donald Trump? Yes. Speaker Pelosi does it every day," Democratic Senator Amy Klobuchar said as she retweeted the picture.

Continue Reading
 
 
Help Raw Story Uncover Injustice. Join Raw Story Investigates for $1 and go ad-free.
close-image