There’s one good way to find out what a gene does, and that’s to break it. Scientists can switch off specific genes in model organisms such as fruit flies, then look for any effects in the embryo or animal. But while flies in the lab are genetically identical, people are not. Variations in genetic makeup and the environment both influence how strongly a gene fault exerts its effects. These are wing discs – structures in the fruit fly larva that will become wings in the adult fly. The one on the left is normal, but the one on the right has a fault in the vestigial gene. By comparing the impact of multiple genetic changes in fruit flies with different genetic backgrounds or raised under different conditions, researchers can start to figure out how all these genetic variations work together with the environment to affect how each individual organism turns out.
Written by Kat Arney
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