Summary
Genetically identical individuals, such as human twins, are expected to be very similar, but they nonetheless exhibit substantial differences in traits and diseases throughout their lives. In controlled laboratory settings where all individuals experience the same environment, genetically identical animals also exhibit differences in important traits, including fertility and lifespan. However, why genetically identical individuals differ from each other for these traits remains incompletely understood. In addition, how non-genetic differences that arise in one generation impact subsequent gene
