The primary cause of this potential thermoregulation instability in the newborn is

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

answer; i do believe that the correct answer is; ///mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis;