Supersize me and my kids: metabolic disorders caused by high-fat diet can be passed on to offspring, study finds
Researchers at the Chinese Academy of Sciences find in an experiment with mice that health problems related to behavioural or environmental changes can be transmitted to children, triggering fears of a ‘smog-affected’ generation in China
Parents who eat too much junk food or who otherwise survive on a high-fat diet can transmit the metabolic disorders they acquire to their children, according to the results of experiments conducted on mice by researchers at the Chinese Academy of Sciences.
The unhealthy behaviour of the male mice was recorded in a tiny molecule called tsRNA that was found to be transmitted via sperm to the embryo, they said in their paper, which was published in the latest issue of the journal Science.
It ran with a separate study showing similar findings by researchers at the University of Massachusetts Medical School in Worcester, the United States.
The two studies suggested that newly acquired traits can be passed on from one generation to the other, which has disturbing implications for parents living in particularly unhealthy or smoggy environments.
The findings are of interest because biologists have generally rejected this hypothesis in favour of another which says that human genes are constantly mutating, rather than being subject to the changing behaviour of an individual.
According to Darwin’s theory of natural selection, Mother Nature decides which traits or species are the fittest to survive.
But before Darwin came along, French biologist Jean-Baptiste Lamarck made the claim that certain forms of behaviour bring a competitive advantage that can help a creature better adapt to its environment.
Prof Duan Enkui, a lead scientist of the Chinese study, said the latest results “support Lamarck’s theory”.
They found that the tsRNA molecules caused by an parent who grew obese from a diet of fatty food could cause the offspring to be inclined to consume abnormally high levels of glucose.
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It could also lead to other disorders such as an insensitivity to insulin, a hormone the pancreas produces to regulate blood sugar levels, they added.
Most previous studies on inherited traits have tended to focus on a creature’s or species’ DNA, whose double-stranded structure provides a stable storage device for the genetic blueprint of life.
In contrast, RNA, which has a single-stranded structure, was considered less stable and only capable of providing an assistant-like role, such as being an interpreter or messenger for the genetic information found in DNA blueprints.
“Our study shows that trait inheritance can be achieved by RNA alone, which takes us into a totally uncharted area,” Duan said.
Prof Meng Anming, a molecular biologist at Tsinghua University in Beijing, said the studies have thrown light on a different way in which traits may be inherited, but that the evidence was not strong enough to challenge the dominant role of DNA and Darwin’s theory of natural selection.
“The effect of the RNA [molecules] may be limited to a certain number of generations,” said Meng, who was not involved in either of the two studies.
“They are side-kicks in comparison to DNA’s dominant and long-lasting role,”
But Meng agreed that if a large group of individuals were compelled to change their behaviour or live under different environmental conditions, it could alter the course of evolution.
For instance, if the chronic smog issue now affecting China were to persist, it could produce a “smog-affected” generation with biological traits different from children born in other countries, he said.
“These [inherited] traits could be negative or positive. They are difficult to predict,” he added.