Athletic male mice give birth to fit pups
Active adult mice have healthy offspring, a Chinese team has discovered. This transmission is not mediated by genes, but by small molecules that regulate gene expression.
Here's a surprising study that proves, if it were still necessary, that there is transmission beyond genes. Researchers from Nanjing University, whose results appeared in the journal Cell Metabolism , decided to investigate the heritability of physical fitness. They wondered if a father's physical activity had a positive effect on the fitness of his future offspring. And they observed that "male mice trained to run on a treadmill [before breeding] transmitted their good physical condition to their male offspring," explains Science .
Specifically, the male calves were able to run longer than those whose fathers were sedentary. They had a higher proportion of a type of muscle fiber that has the characteristic of not tiring during prolonged contractions. Furthermore, when fed a high-fat diet, they did not become obese or diabetic.
The American magazine points out that the majority of heritable characteristics are passed from parents to children through genes: this is the case, for example, for lung volume, which logically increases the chances of becoming a good runner. But for our running mice and their offspring, the explanation lay elsewhere.
For several years, it has been known that an individual's experiences, lifestyle, and environment transform their DNA, notably by adorning it with sugars. These reversible modifications, which modulate gene activity, can be passed on to the next generation.
“ Recent research has shown that microRNAs in sperm are one way epigenetic information is passed [to offspring] ,” explains Science . MicroRNAs are tiny pieces of RNA that play a role in gene regulation. Their discoverers were awarded the Nobel Prize in Medicine last year.
An analysis of the RNA in the sperm of the athletic mice (the team had them run for two weeks on a treadmill before mating with non-athletic females) showed particularly high levels of 10 microRNAs. The researchers believe this is how the young males acquired good physical condition.
