6. In humans, having a widow’s peak (W) is dominant to not having a widow’s peak (w). Sally has a widow’s peak. If Sally has a son who does not have a widow’s peak, what genotype can the father NOT be? 7. The ability to roll the tongue inward in humans is determined by the dominant gene T. From a couple both able to roll the tongue, a child is born. The child is unable to roll the tongue. What is the genotype of each of the parents? Solution 6.ans-The father cannot be WW As one allele comes from father as Sally is Ww. 7 ans- the genotype of each of the parents is Tt On solving by Punitt square the offsprings are TT,Tt,Tt& recessive tt. The recessive tt genotype offspring cannot roll tongue.