Well, it wasn't exactly from Heaven. These were fallen angels wanting to change their DNA to be able to copulate with human women. I understand it isn't canon but everyone knew about in NT times. It was available and well read.
That was quite a stretch.
Watson and Crick completed their model, which is now accepted as the first correct model of the double helix of DNA. On 28 February 1953 Crick interrupted patrons' lunchtime at The Eagle pub in Cambridge, England to announce that he and Watson had "discovered the secret of life".That's only a month before I was born. Nobody had even heard of DNA until my lifetime. How could they have known about fallen angels wanting to change their DNA if nobody had even heard of it?