I'd love to get a confirmation on if that is what this means? Seems odd to reference it the way they did if we all have the gene. My reading was more that it

I'd love to get a confirmation on if that is what this means? Seems odd to reference it the way they did if we all have the gene. My reading was more that it would be like the gene for a certain hair color. But, my reading is a very naive one, to be sure.