Alexandria's Genesis is a rumoured mutation, turning people into long-living “perfect human beings” marked by purple eyes, extremely fair skin (that does not get sunburned), dark brown scalp hair (but no body hair), and other beauty traits to go with their strength and vitality. Rumours of this online go back to at least 2005 and a number of New Agers insist it's a genuine condition.
It's not, it was made up in 1998 by Daria fanfic writer Cameron Aubernon to explain her Mary Sues. How it became a rumoured real mutation is unknown, and it greatly confused the writer herself.
Aubernon said on her tumblr it was "a projection of my personal gender identity and body image issues", as well as "simply a bad mashup of Daria, Art Bell, Twilight, witchcraft and Cylon skinjobs adopted by New Agers and others who should know better, but don’t and won’t."