Research carried out by the University of Cambridge has revealed a way in which a parent's experiences can be passed on to their offspring's genes.
The research, published 25 January in the journal Science, examined the way in which genes in the primordial germ cells of a mouse were passed on via epigenetics -- a system that turns genes on and off.
Epigenetics concerns the inheritance of gene expression through the passing on of DNA. A chemical tag, known as an epigenetic mark, is attached to DNA that subsequently tells a cell to use or ignore a particular gene. The most common of these marks is known as a methyl group, an alkyl derived from methane. When it binds itself to DNA, by a process called methylation, it prevents protein from being added to the gene, and as a result, turns it off.
Epigenetic marks are usually erased between each generation due to the way in which primordial gene cells (PGCs, precursors to sperm and eggs) restructure the genetic information ready for the next generation.
The Cambridge study, led by Jamie Hackett, discovered how the methylation marks were erased by the PGCs, resetting them for the next generation. As the PGCs divided, they broke down the methylation marks and diluted them with each divide. The study claims that such an understanding of epigenetic resetting "could be exploited to deal with adult diseases linked with an accumulation of aberrant epigenetic marks, such as cancers, or in 'rejuvenating' aged cells."
The observation of the PGCs also yielded a further discovery.
Not all methylation marks were reset, with some escaping intact to be passed on to offspring. "This is important because aberrant methylation could accumulate at genes during a lifetime in response to environmental factors, such as chemical exposure or nutrition, and can cause abnormal use of genes, leading to disease. If these marks are then inherited by offspring, their genes could also be affected."
Hackett urged that the new findings should result in theories of epigenetic inheritance being reassessed. "It seems that while the precursors to sperm and eggs are very effective in erasing most methylation marks, they are fallible and at a low frequency may allow some epigenetic information to be transmitted to subsequent generations," he added. "The inheritance of differential epigenetic information could potentially contribute to altered traits or disease susceptibility in offspring and future descendants."
What the research doesn't yet make clear is what the consequences of epigenetic inheritance might have in humans.
Azim Surani, principal investigator of the research, said: "The new study has the potential to be exploited in two distinct ways.
First, the work could provide information on how to erase aberrant epigenetic marks that may underlie some diseases in adults.
Second, the study provides opportunities to address whether germ cells can acquire new epigenetic marks through environmental or dietary influences on parents that may evade erasure and be transmitted to subsequent generations, with potentially undesirable consequences."
This article was originally published by WIRED UK
