As for the presence of large NGF [nerve growth factor] sources in snake venom and male genital organs, they may be conceived as instances of bizarre evolutionary gene expression.
"The Saga of the Nerve Growth Factor: Preliminary Studies, Discovery, Further Development".
![As for the presence of large NGF [nerve growth factor] sources in snake venom and male genital organs, they may be conceived as instances of bizarre evolutionary gene expression.](http://cdn.quoteddaily.com/images/rita-levi-montalcini/as-for-the-presence-of-large-ngf-nerve-growth-factor-sources-in-snake-venom-and-male-genital-organs-they-may.jpg)