Sex linked gene question?

In humans, spotted teeth are caused by a dominant sex linked gene. a man with spotted teeth whose mother had normal teeth marries a woman with normal teeth. therefore, all of their daughters will have spotted teeth.





I dont understand the conclusion, because i thought the daughters would only be heterozygous carriers.





i think while typing the question i just realized why....since the trait is dominant they would express it phenotypically, and in this case they wouldnt just be carriers. is this right?

Sex linked gene question?
That is a correct conclusion. The gene is dominant (yes, sex-linked genes are occasionally dominant). Every time they have a daughter, she has to get the one X chromosome her dad can supply (and the sex linked gene for the spotted teeth is on that X chromosome). So regardless of what she gets from her mom, she will have one dominant X gene for spotted teeth, so she will express the trait.
Reply:A dominant sex-linked gene is expressed whenever it is present so heterozygous individuals, such as daughters, have spotted teeth. You could only be a carrier if it were a recessive gene.