Researchers at Johns Hopkins have found that epigenetic marks on DNA-chemical marks other than the DNA sequence-do indeed change over a person's lifetime, and that the degree of change is similar among family members.
Reporting in the June 25 issue of the Journal of the American Medical Association, the team suggests that overall genome health is heritable and that epigenetic changes occurring over one's lifetime may explain why disease susceptibility increases with age.
"We're beginning to see that epigenetics stands at the center of modern medicine because epigenetic changes, unlike DNA sequence which is the same in every cell, can occur as a result of dietary and other environmental exposure," says Andrew P. Feinberg, M.D., M.P.H, a professor of molecular biology and genetics and director of the Epigenetics Center at the Johns Hopkins School of Medicine. "Epigenetics might very well play a role in diseases like diabetes, autism and cancer."
If epigenetics does contribute to such diseases through interaction with environment or aging, says Feinberg, a person's epigenetic marks would change over time. So his team embarked on an international collaboration to see if that was true. They focused on methylation-one particular type of epigenetic mark, where chemical methyl groups are attached to DNA.
"Inappropriate methylation levels can contribute to disease-too much might turn necessary genes off, too little might turn genes on at the wrong time or in the wrong cell," says Vilmundur Gudnason, MD, PhD, professor of cardiovascular genetics at the University of Iceland director of the Icelandic Heart Association's Heart Preventive Clinic and Research Institute. "Methylation levels can vary subtly from one person to the next, so the best way to get a handle on significant changes is to study the same individuals over time."
The researchers used DNA samples collected from people involved in the AGES Reykjavik Study (formerly the Reykjavik Heart Study). Within the study, about 600 people provided DNA samples in 1991, and again between 2002 and 2005. Of these, the research team measured the total amount of DNA methylation in each of 111 samples and compared total methylation from DNA collected in 2002 to 2005 to that person's DNA collected in 1991.
They found that in almost one-third of individuals, methylation changed over that 11-year span, but not all in the same direction. Some individuals gained total methylation in their DNA, while others lost. "What we saw was a detectable change over time, which showed us proof of the principle that an individual's epigenetics does change with age," says M. Daniele Fallin, Ph.D., an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health. "What we still didn't know was why or how, but we thought 'maybe this, too, is something that's heritable' and could explain why certain families are more susceptible to certain diseases."
The team then measured total methylation changes in a different set of DNA samples collected from Utah residents of northern and western European descent. These DNA samples were collected over a 16-year span from 126 individuals from two- and three-generation families.
Similar to the Icelandic population, the Utah family members also showed varied methylation changes over time. But they found that family members tended to have the same kind of change-if one individual lost methylation over time, they saw similar loss in other family members.
"We still haven't concretely figured out what this means for health and disease, but as an epidemiologist, I think this is very interesting, since epigenetic changes could be an important link between environment, aging and genetic risk for disease," Fallin says.
Audrey Huang | EurekAlert!
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy