The ultimate creation of evolutionary adaptation has been eliminated by the simplest. But such first contacts virtually disappear from SF in the 1950s. A perfect expression of this alien image that merges these two dimensions of invasion is presented by one of the most successful images of the Star Trek Next Generation series, the Borg. We will add your biological and technological distinctiveness to our own. You will be assimilated.
Resistance is futile.
Anticipating this most intriguing challenge to human survival and autonomy that the Borg represent, much of Octavia Butler's fiction uniquely challenges SF notions of first contact. Our genetic material for yours. This process is carefully defined not as interbreeding but as genetic engineering. The Anxiously do this naturally. The trilogy's protagonist, Lilith, an African American, is suspicious of such altruism, but the Oankali have saved the humans from a global war, and they are regenerating the planet.