;Embryogenesis : The role of EVI1 in embryogenesis and development is not completely understood, but it has been shown that EVI1 deficiency in mice is an embryonic lethal mutation, characterized primarily by widespread hypocellularity and poor / disrupted development of the cardiovascular and neural system.
12.
It updates and complements the previous Synthetic Theory having in view that the natural selection underlined by Charles Darwin is to be applied only to phenotype, so that certain phenomena ( such as lethal mutations ) were not sufficiently taken into account by this old model.
13.
Such studies cannot conclusively establish that one method is better than another, as randomized trials can, but unless it is understood " why " treatment X is better than treatment Y, application of results of quantitative studies will often lead to " lethal mutations " Many studies are mixed , simultaneously combining aspects of both quantitative and qualitative research, as appropriate.
