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Want Big Muscles?

Understanding more about how muscle growth and size is controlled

14 April 2020

Want Big Muscles?

From a body-builder’s bulging bicep to the tiny flight muscles that keep a fruit fly’s wings beating, muscles are all made from bundles of long fibres divided into short, repeated segments called sarcomeres. When an animal makes a move, interlocking molecules within the sarcomere move past each other and cause the muscle to contract. These images show flight muscle fibres from six fruit flies, each with a different genetic change affecting a structure called the Z-disc (yellow), which marks the end of each sarcomere. Changes in a gene called Zasp affect the size of the Z-disc, in turn affecting the diameter of the fibre and altering the overall size and function of the muscle. Zasp is also involved in setting sarcomere size in the muscles of other animals, including humans. Some of these genetic changes mimic the effects seen in some types of muscle disease (myopathies), pointing towards future treatments.

Written by Kat Arney

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BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

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