Indeed, reduction in retrograde transport through mutations in dynactin52, which is an activator of the retrograde motor cytoplasmic dynein53, provokes motor neuron disease in humans.

In response, it sent letters of notification advising practitioners of the FDA’s jurisdiction over cytoplasmic transfer.

Yet one of the physicians who led the cytoplasmic transfer effort nearly 20 years ago contends it’s impossible to draw such a clean conclusion.