There are mutants like Iceman that have bodies that are or can become something that is not flesh and blood. With people like that their powers can't be maintained through their X-Genes since, as living ice or whatever, they no longer have cells or DNA. Some can even be completely destroyed and remake themselves from things in the environment (continuing with Iceman as an example it would be moisture in the air or anywhere) which, since they originate outside the person's body couldn't even have once been DNA containing the person's X-Gene.
Beast is trying to duplicate the missing X-Gene in people hoping to recreate mutants. I think he should figure out how people who can use their powers without normal bodies (and therefore without the X-Gene) can do what they do and then duplicate that instead of just trying to make the gene.
Am I right? Wrong? Agree? Disagree? Your ideas?