The number of mutations that can contribute to aging could be significantly higher than previously thought, according to a new study on fruit flies. A study by scientists at the University of Linköping, Sweden, supports a new theory about the type of mutation that may be behind aging. The results are published in BMC Biology.
We live, grow old and die. Many functions of our bodies deteriorate slowly but surely with age and eventually the body dies. This thought may not be very encouraging, but most of us have probably accepted that this is the fate of all living things ̵
“The evolution of aging is somehow a paradox. Evolution causes constant adaptation in organisms, but it has not led to their aging,” said Urban Friberg, a senior lecturer in the Department of Physics, Chemistry and Biology at Linköping University and head of the study. .
Nearly 70 years ago, evolutionary biologists proposed two theories about two different types of mutations that contribute to aging. Both mutations have a detrimental effect as the body ages – leading to aging – while they are either beneficial or neutral in early life. However, researchers have not been able to determine which of the two types of mutations contributes the most to aging, despite experimental studies.
A new theory was proposed a few years ago, which suggests that aging is caused by mutations with a detrimental effect at the beginning of life and whose negative effects increase with age. Those who support this hypothesis believe that many of the mutations that occur have negative effects from the outset, compared to the normal gene variant.
The now published study describes experiments to test the theory of mutations that have a lifelong harmful effect and contribute to aging. The authors used one of the best studied animals in the world, namely the fruit fly or Drosophila melanogaster. They tested 20 different mutations that they had placed in the genetic material of the flies. For each individual mutation, they examined a group of flies with the mutation and a control group without it. Each mutation had a specific, visible effect that made it easier to track, such as a slightly different appearance of the wings or a different shape of the eyes.
As the body ages, the likelihood of dying increases and its ability to reproduce decreases. Researchers have determined the fertility of fruit flies and used it as a measure of aging. They counted the number of eggs laid by each female at the beginning of life, after two weeks and finally after another two weeks (which is adulthood for a fruit fly!). The researchers wanted to see if the difference between the flies with the mutations and the control group changed with age. The results support the theory they tested. Most of the mutations had a negative effect on the fertility of fruit flies at the beginning of life and most of them also caused faster reproductive aging.
“The results suggest that mutations that are harmful in early life may also contribute to aging. In this way, mutations that lead to aging may be significantly more common than previously thought.” says Martin Inati Brengdal, a PhD student in the Department of Physics, Chemistry and Biology and lead author of the study.
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“Harmful mutations show increasing negative effects with age in Drosophila melanogaster”, Martin I. Brengdal, Christopher M. Kimber, Phoebe Elias, Josephine Thompson and Urban Friberg, (2020), BMC Biology, published online September 30, DOI: 10.1186 / s12915-020-00858-5
Provided by the University of Linköping
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