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.

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.

ADVERTISEMENT

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.

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.

ADVERTISEMENT

“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.

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.

ADVERTISEMENT

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.

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.

ADVERTISEMENT

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.

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.”

ADVERTISEMENT

(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

Facebook

US senator calls for investigation into FaceApp over security concerns

Published

on

Popular Russia-based application FaceApp, which allows users to change their appearance to look older or younger, came under fire in the United States Wednesday, with one senator urging an FBI investigation.

Senate Minority Leader Chuck Schumer called for the FBI and the FTC, the US consumer protection body, to "look into the national security & privacy risks" connected to FaceApp, which is used by millions of Americans but was developed by a Saint Petersburg-based company.

"FaceApp's location in Russia raises questions regarding how and when the company provides access to the data of U.S. citizens to third parties, including potentially foreign governments," the New York senator said in a letter to the FBI.

Continue Reading

Facebook

First US murder conviction overturned using DNA, family tree evidence

Published

on

An American man was exonerated Wednesday for a decades-old murder he did not commit, using evidence based on DNA and a genetic family tree, the first such result using a revolutionary investigative technique.

Christopher Tapp, 43, had served 20 of his 30-year sentence for the 1996 rape and murder of Angie Dodge.

On Wednesday, a court in the state of Idaho completely overturned his conviction based on evidence found with "genetic genealogy" -- the technique used to identify the suspected "Golden State Killer" by making DNA matches with his distant relatives.

Continue Reading
 

Facebook

Buzz Aldrin has landed — for the Apollo 11 anniversary

Published

on

The suspense had been building for 24 hours: would Buzz Aldrin, the second man to walk on the Moon, show up Wednesday night in Huntsville, Alabama -- nicknamed "Rocket City" for the nearby NASA space flight center?

Public appearances by the former astronaut, now 89, are rare. On Tuesday, he left his former Apollo 11 crewmate Michael Collins in the lurch.

Aldrin declined to join him at the Kennedy Space Center in Florida, where the two were supposed to appear together on NASA TV to mark the 50th anniversary of their mission (Neil Armstrong died in 2012).

Continue Reading
 
 
 

Copyright © 2019 Raw Story Media, Inc. PO Box 21050, Washington, D.C. 20009 | Masthead | Privacy Policy | For corrections or concerns, please email [email protected]

Enjoy Summer! Try Raw Story Ad-Free for $1. Invest in Progressive Journalism.
close-image