Epigenetics News and Research: July 2019
Though we are still very much at the initial stages of understanding the role epigenetics can play in our future, more and more research is being carried out, which suggests it can be used to better understand - and in some cases prevent - illness, weight, allergies and much more.
From poverty to childhood allergies, and even sex-switching, over the last few months there have been some incredibly interesting studies around epigenetics. Here’s a few of the ones that stood out to us the most.
Poor wealth may epigenetically mean poor health
Poverty is an increasing problem all over the world, with one of the main causes believed to be the inability to afford a nutritious diet or proper health care. However, in a recent study out of Northwestern University, Dr. Thomas McDade led a team of researchers to see if there are underlying mechanisms responsible for the relationship between our socioeconomic status (SES) and health.
The team evaluated leukocytes, obtained from the Cebu Longitudinal Health and Nutrition Survey, of 489 Filipino participants of different incomes, educations and living situations. They found that living in poverty can affect DNA methylation levels on the genome, and leave a person susceptible to developing health problems later in life.
DNA methylation is an epigenetic mechanism, which helps regulate gene expression. Evidence from the study showed that people who live in poverty experience altered levels of DNA methylation - approximately 2500 CpG sites over 1500 genes, the equivalent of 10 percent of the genes in the genome. Genes associated with increased DNA methylation were related to skeletal development, immune response and neurological development, demonstrating the cause for future health concerns.
Source: McDade T. et al (2019). Genome‐wide analysis of DNA methylation in relation to socioeconomic status during development and early adulthood. Am J Phys Anthropol. 169: 3–11.
Reference: Hilary Hurd Anyaso, Northwestern Now, Poverty leaves a mark on our genes Northwestern University, April 05, 2019.
Epigenetic age linked to allergic conditions in children
The diagnosis of allergies and asthma among children has risen tremendously in the last decade, though this is partly due to higher awareness. But what is driving this increase?
This article looks at the ‘allergic march’, the term given when a child grows out of one sensitivity and then develops another one later one, and how the role of epigenetics can determine the biological mechanisms that play a role in this.
In a recent study, scientists looked at how the association between DNA methylation age (DNAmAge) and epigenetic age acceleration within childhood asthma and allergies. The investigators examined DNA from blood samples taken from the children participating in the large cohort at various time periods: birth, early childhood, and mid-childhood. DNA methylation levels were then recorded and DNAmAge calculated using the Horvath method - Methylation signifies a chemical change to DNA that can either activate or repress gene expression without altering the underlying genetic code.
The overall results indicated that by mid-childhood, advanced DNAmAge correlated to higher levels of IgE - antibodies found in the blood of allergic individuals - as well as increased risk for environmental and food allergies, and asthma.
According to Dawn DeNeo, MD, MPH, senior author of the study, “If we can target our future investigations on early exposures such as nutrition, we may be able to use epigenetic clocks to find out what changes we can make to modify this trajectory toward the development of asthma and allergy.”
Source: Peng C et. al. (February 2019). Epigenetic age acceleration is associated with allergy and asthma in children in Project Viva. J Allergy Clin Immunol.
Reference: Brigham and Women’s Hospital. “Study Links Epigenetic Age with Childhood Allergy, Asthma: Ticking of DNA methylation clocks tied to higher odds of asthma and atopy in children,” Brigham and Women’s Hospital Press Release. April 2019.
Sex-switching super powers of a tropical fish might be due to stress
Some animals - more than you may realise - have the ability to undergo a genetic upheaval. Basically, they turn from one gender to another. In a study, co-lead by Dr Erica Todd, from the University of Otago, they reviewed the sex-change of female Bluehead Wrasse, from a genetic perspective.
A female Wrasse changes from female to male over a 10-day period, upon the last male in the harem disappearing. According to Dr Todd, sex isn’t always determined by chromosomes but it is determined by a cue; in this case, that cue is the male leaving.
To track the sex transformation, researchers removed males from harems and then observed the physical and genetic changes of dominant fish. As the fish transformed, so did its behaviours, genetics and physical appearance.
Some of the changes observed were in the fish's epigenetics. This means there were changes in chemical marks in the DNA, changing the way it was read, rather than a change in the DNA sequence itself.
The results suggest that epigenetic and genetic changes occur in tandem, alongside physical changes to ovaries and testes, said Phillip Munday, an expert in coral reef ecology at James Cook University who was not involved with the study - but Dr Todd said her research points to stress being the trigger.
According to Dr Todd, the results suggested cortisol levels — a stress hormone — peaked in dominant females when the large males were removed, leading the researchers to hypothesise this may start the sex-change chain reaction.
The article also looks at how increased water temperature in other animals can be known to provoke a sex-change.
Reference: Erica Todd, researcher at the University of Otago, co-lead author on the study, as published in Science Advances. 10th July, 2019.
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