Synthetic regulatory elements such as enhancers promise to be a powerful tool to direct gene products to particular cell types in order to treat disease by activating beneficial genes or by halting aberrant cell states. 
Since 2022, artificial intelligence and transfer learning strategies have led to a better understanding of the features of regulatory DNA sequences, the prediction, and the design of synthetic enhancers. 
Building on work in cell culture, synthetic enhancers were successfully applied to entire living organisms in 2023. Using  deep neural networks, scientists simulated the evolution of DNA sequences to analyze the emergence of features that underly enhancer function. This allowed the design and production of a range of functioning synthetic enhancers for different cell types of the fruit fly brain. A second approach trained artificial intelligence models on single-cell DNA accessibility data and transferred the learned models towards the prediction of enhancers for selected tissues in the fruit fly embryo. These enhancer prediction models were used to design synthetic enhancers for the nervous system, brain, muscle, epidermis and gut.