Sixties or Seventies film where there is a flash and lots of the population disappear, leaving behind their clothes. A father and his kids try to make it back to their home to the mother of the family: when they get there her clothes are on the bed (she didn't survive) and the camera swoops out of the window to end on a shot of a sunrise/sunset on the beach. From what I can remember, survivors were protected by a specific gene: in the case of the father, he had the gene and had passed it on to his children, but the mother didn't have the gene. Does anybody know what this film is, as I've been trying to find it for years.....
One reviewer talks about the film's climactic scenes: