Recent content by elegans

See Morgan's white eyed flies. Every generation of males will have some with white eyes because the mutation is sex linked, in this case it is on the X-chromosome. Flies are a little different than people, because their males are determined by having one X-chromosome, and females have two...

Try any type of sex-linked disease. For example, males pass on a single Y chromosome to male offspring, and it is always penetrant.