Eventually there comes a point in a human’s life where we won’t get any taller. For some of us it’s much too early, as all our classmates seemingly sprout up like sunflowers in the following years.
This is all related to puberty, but how humans – or any other animal – are triggered to stop growing is not fully known. Researchers turned to the fruit fly Drosophila melanogaster to try and unravel the mystery.
“We know that the onset of puberty is getting younger and younger,” said Professor Alexander Shingleton, a biologist at the University of Illinois Chicago.
“But in order to understand why something is changing, you need to understand how it works.”
Fruit flies don’t undergo puberty like we do, but they do go through something even more extreme – metamorphosis. This is where larvae become adult flies.
Some insects trigger the metamorphosis process due to size of the larvae. This is called a ‘stretch receptor’.
But the researchers suggested that this wasn’t the whole story in Drosophila and instead hypothesised that the steroid hormone ecdysone could play a role.
Using data about the growth and time of metamorphosis in fruit flies, the researchers made a mathematical model to try and uncover what was happening.
The model suggested that the gland that produces ecdysone eventually flicks a switch to stop growing once the ecdysone reaches a certain level.
Before metamorphosis begins the prothoracic gland receives nutritional information to drive ecdysone production. But once ecdysone reaches a threshold, the nutritional information is no longer required, and the body gets ready to change.
Of course, this can’t be directly ported from flies to humans, but it does give us more information about how it could be related. Plus the team want to see more studies like this in mammals.
Despite that, Shingleton believes that the fruit fly experience is more similar to humans that you might think. He suggests that both involve similar steroid hormones and both fruit flies and humans convey nutritional information via insulin.
The research was published in the Proceedings of the National Academy of Sciences.
Originally published by Cosmos as One day you’ll never get taller. Scientists look at flies for why
Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
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