If a female of some animal or other, carrying a freshly-fertilized zygote, and her species happened to have all the necessary potential characteristics, and a flood of ionizing radiation went through the zygote at exactly the right time, and it managed to hit just the right genes in just the right way ...
"The Asses of Balaam"
Gordon Randall Garrett
This, however, appeared later as a product of the further evolution of the zygote, and the reduction division was correspondingly postponed.
"Darwin and Modern Science"
A.C. Seward and Others
Firstly, there are those variations consequent upon a variation in the constitution of the protoplasm of a particular zygote, and independent of the environment in which the organism develops, save in so far as this simply calls them forth: these are the so-called genetic or mutational variations.
"Darwin and Modern Science"
A.C. Seward and Others