Hello @fonpet,
Your story has an interesting core. However, as @medemausi's comment indicates below, you keep us guessing about the genetic 'gift'. It would be good for you to let the reader into this mystery (for you do make it a mystery) early on in the story. Even in the end, we're not sure what the gift is. It has something to do with dentition, but we can't understand exactly what. Does the genetic trait have a name?
This would be important for the reader's to understand your evolution as a character.