The precise mechanism that "turns the inheritance of environmental influences on and off" has been pinpointed, says a team at Tel Aviv University.
Epigenetics refers to the idea that certain genetic expressions -- such as obesity, mental illness, memory, addiction and more -- that are affected or altered via environmental factors can be inherited, despite the fact that offspring were never subject to these environmental factors themselves. Studies have suggested children can inherit 'abnormal metabolisms' from overweight fathers and confirmed that certain inherited genes retain a memory of chemical exposure. And UK based epigenetics company Cambridge Epigenetix just received $21million (£15million) in funding from Google's funding arm GV.
Now, the Tel Aviv team says it has identified a "small RNA inheritance" that dictates how certain cells are regulated between generations. The research team had previously shown that worms inherited "small RNAs" following the starvation of their parents -- which it said "helped prepare [the worms'] offspring for similar hardships". The latest research, also conducted on worms, has now "revealed an active, tuneable inheritance mechanism that can be turned 'on' or 'off'". "We discovered how to manipulate the transgenerational duration of epigenetic inheritance in worms by switching 'on' and 'off' the small RNAs that worms use to regulate genes," said Oded Rechavi, who lead the study.
"These switches are controlled by a feedback interaction between gene-regulating small RNAs, which are inheritable, and the genes that are required to produce and transmit these small RNAs across generations. The feedback determines whether epigenetic memory will continue to the progeny or not, and how long each epigenetic response will last." "Until now, it has been assumed that a passive dilution or decay governs the inheritance of epigenetic responses," Rechavi said. "But we showed that there is an active process that regulates epigenetic inheritance down through generations." The team now hope to study the same genes in humans to find out "exactly how these genes affect the duration of epigenetic effects", as well as establish whether or not they exist in humans.
Not everyone is as hopeful about epigenetics. Maurizio Meloni, research fellow in sociology at the University of Sheffield, warned that epigenetics "may bring back eugenic thinking". "There certainly is no shortage of war, famine, exploitation, destruction, epidemic and trauma. Knowing that some of this can leave a biological trace in our genes -- which can even be transmitted to future generations -- could be problematic," he writes at The Conversation. Pointing to studies that link poverty with a particular epigenetic marker and low birth weight in African-American babies with a history of slavery, he warns that they "could be used by racist groups to argue for the 'acquired inferiority' of specific populations". "In focusing on the environment as a cause for many unwanted conditions, epigenetics has the potential to advance social justice," he writes. "But we need to remember that it is no guarantee of a more inclusive society. Social values often decide how we implement science, rather than the other way round."