The Vacation Solution - S5-E16
Howard: I'm not signing a pre-nup.
Penny: Alright, Howard Wolowitz, listen up. You sign anything she puts in front of you because you are the luckiest man alive. If you let her go, there is no way you will be able to find anyone else. Speaking on behalf of all women, it is not going to happen, we had a meeting!
The Countdown Reflection - S5-E24
Sheldon: All right, my turn. Howard, Bernadette. DaQH Daj mo...DaQH...
Bernadette: Sheldon! I told you no Klingon.
The Countdown Reflection - S5-E24
Amy: Bernadette, I want to thank you for allowing me to be your maid of honor. I also want you to know that I will be happy to do it again if this marriage craps out.
Suggested correction: Genes can be dormant. Which allows them to skip generations. Therefor Missy's children could actually get the "mutated" gene. This is especially true since Sheldon and Missy are twins. Also, since the episode is about who out of Leonard, Howard or Raj, Sheldon would allow to "mate" with his sister, there is the added "insurance" of getting any smart genes from any of the 3 Lothario's mentioned above.
If you are going to try to argue with a geneticist about genetics, please use the correct terms. Sheldon is not referring to a recessive gene - there is no such thing as a dormant gene - he is speaking of a randomly mutated gene. Those are the words he used. If he had inherited a homozygous recessive karotype - one recessive gene from each of his parents - then somewhere in his family tree there would similarly gifted people, in which case he would use the correct term - a recessive gene. If Missy is a heterozygotic dominant karotype possessing the recessive gene for super-genius and the dominant for ordinary intelligence then mating her with Howard, Raj or Leonard would be a waste of time as their dominant genius gene would prevent the recessive super-genius gene from being expressed in the phenotype of the resulting child. The child would be highly intelligent but not on Sheldon's standards. It doesn't matter if Sheldon does not know any of this as he refers several times to a randomly mutated gene, not a recessive one. Missy does not carry the super-genius gene. The posting is correct.
Sheldon is prone to magical thinking when necessary to preserve his obsessive need to control his environment. He may have simply ignored the flaw in his reasoning, as even the most intelligent humans do when venturing outside their ares of expertise. He may be interested in the science of genetics, but his Ph.D. in physics doesn't qualify him as an expert in that field.