For many inherited diseases, cells deteriorate rapidly or undergo mutations when they divide. However, through cloning, scientists can study the diseased cell, which causes errors in others. By cloning a specific mutated cell, scientists can study the development of a disease (Jaenisch 1). Instead of allowing the cell to divide on its own and change its structure each time, exact replicas can be produced, allowing researchers to perform experiments on one independent variable at a time. By researching the inner workings of mutated cells, scientists can uncover more information about “healthy monoallelic expression of imprinted genes…[and] the sperm and oocyte genomes…in the zygote genome” (Jaenisch 2 ). . The zygote is a pre-fetus and its healthy formation is vital for the proper development of humans. By researching cloning, scientists can understand a cell's harmful mutations and develop a cure or vaccine against them. Scientists can then, after figuring out how to stop mutations, find a way to stop human cells from deteriorating and discover a way to extend the lifespan of a typical human being.