Featured Research

from universities, journals, and other organizations

Researchers extend human epigenomic map

Date:
August 8, 2013
Source:
Harvard University
Summary:
New research describes the dynamics of DNA methylation across a wide range of human cell types. Chemically, these marks are the addition of a methyl group -- one carbon atom surrounded by three hydrogen atoms -- anywhere a cytosine nucleotide sits next to a guanine nucleotide in the DNA sequence.

Ten years ago, scientists announced the end of the Human Genome Project, the international attempt to learn which combination of four nucleotides -- adenine, thymine, cytosine, and guanine -- is unique to Homo sapiens DNA. This biological alphabet helped researchers identify the approximately 25,000 genes coded in the human genome, but as time went on, questions arose about how all of these genes are controlled.

Now, Harvard Stem Cell Institute Principal Faculty member Alexander Meissner, PhD, reports another milestone, this time contributing to the multilayered NIH-funded human Roadmap Epigenomics Project. Epigenetics is the study of how the over 200 human cell types (e.g., muscle cells, nerve cells, liver cells, etc.) can have an identical complement of genes but express them differently. Part of the answer lies in the way that DNA is packaged, with tight areas silencing genes and open areas allowing for genes to be translated into proteins. Stem cells differentiate into various cell types by marking specific genes that will be open and closed after division.

New research by Meissner, published online as a letter in the journal Nature, describes the dynamics of DNA methylation across a wide range of human cell types. Chemically, these marks are the addition of a methyl group -- one carbon atom surrounded by three hydrogen atoms (CH3) -- anywhere a cytosine nucleotide sits next to a guanine nucleotide in the DNA sequence.

Meissner's team, led by graduate student Michael Ziller, at Harvard's Department of Stem Cell and Regenerative Biology mapped nearly all of the 28-million cytosine-guanine pairings among the 3-billion nucleotides that make up human DNA, and then wanted to know which of these 28 million are dynamic or static across all the cell types.

"When we asked, how many of them are changing, the answer was a very small fraction," said Meissner. The researchers found that eighty percent of the 28-million cytosine-guanine pairs are largely unchanged and might not participate in the regulation of the cell types, while the dynamic ones sit at sites that are relevant for gene expression -- in particular distal regulatory sites such as enhancers. "Importantly this allows us to improve our current approaches of mapping this important mark through more targeted strategies that still capture most of the dynamics," Meissner said.

The methylation map generated by the Meissner lab is part of a larger National Institutes of Health (NIH) consortium to look at all of the different epigenetic modification that are found across a large number of human cell and tissue types. Earlier this year, the Meissner's lab recorded all of the gene expression and multi-layered epigenetic dynamics that take place in early stem cell differentiation when they prepare to divide into their next fated cell type.

In addition to his roles at Harvard, Meissner is affiliated with the Broad Institute and the New York Stem Cell Foundation. Only a graduate student in 2007, he has quickly established himself as a leader in the epigenetics field. "It just happens to be that we're at the right time and at the right place, both physically and sort of in time, " he said. "Just five years ago, we would have had the same question, but we wouldn't have had the same tools to answer the question."


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Michael J. Ziller, Hongcang Gu, Fabian Mόller, Julie Donaghey, Linus T.-Y. Tsai, Oliver Kohlbacher, Philip L. De Jager, Evan D. Rosen, David A. Bennett, Bradley E. Bernstein, Andreas Gnirke, Alexander Meissner. Charting a dynamic DNA methylation landscape of the human genome. Nature, 2013; DOI: 10.1038/nature12433

Cite This Page:

Harvard University. "Researchers extend human epigenomic map." ScienceDaily. ScienceDaily, 8 August 2013. <www.sciencedaily.com/releases/2013/08/130808170310.htm>.
Harvard University. (2013, August 8). Researchers extend human epigenomic map. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2013/08/130808170310.htm
Harvard University. "Researchers extend human epigenomic map." ScienceDaily. www.sciencedaily.com/releases/2013/08/130808170310.htm (accessed April 21, 2014).

Share This



More Health & Medicine News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) — Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) — In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) — A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) — The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins