The human genome is a complete set of nucleic acid sequences encoded as DNA within the 23 chromosome pairs in a cell nuclei. The complete set of human genome contains about 3 billion base pairs, amounting up to 750 megabytes of data. Some of the genes are protein coding genes. Each of these genes are responsible for several biological processes. All this data is stored in the nuclei of every cell in the human body. Gene editing is a method to edit the DNA of a living organism. Editing the DNA can lead to the changes in traits in the organism. CRISPR, a tool invented in 2009 has made it a lot easier to edit genes. Animals share a lot of genes. Mice and humans share about 85 percent of genes. Genes are changed on the mice and the effects are studied. This will help better predict the effect on humans. In this case, it has applications both in understanding a new disease or understanding the effect of a medicine. Gene therapies is a way to prevent and treat diseases in humans.