On the Question of Cyclotation

Alas, I remember almost nothing about the story “On the Question of Cyclotation.” There was, it seems, an alien from the future, and his fate was a tragic one. And, it seems, he brought the protagonist—our contemporary—a terrible message about mankind’s original doom. It turns out that in the genes of mankind there is—at the time the species Homo sapiens sapiens was created by our ancestors, scientists from some supercivilization—a biological bomb designed for an “automatic stop” in some generation… Something like that. The beginning of one of the drafts has been preserved in the archive. The clean copy vanished without a trace. Strange, isn’t it? Some mysterious story. Especially since, judging from letters, this story was sent in the summer of 1964 to the “Ural Pathfinder,” and it was even, supposedly, received there favorably. But was it published there? I don’t think so. By God, it’s a strange story.
© Boris Strugatsky. “Comments on the Journey’s End”