This pedigree supports the fact that the widow's peak is due to a dominant allele, because if it were due to a recessive allele and both parents show the recessive phenotype, then . none of the sons would have a widow's peak none of the sons would have a widow's peak all of the daughters and none of the sons would have a widow's peak all of the daughters and none of the sons would have a widow's peak none of the daughters would have a widow's peak none of the daughters would have a widow's peak all of the offspring would have a widow's peak