How are Sex-linked Traits Inherited?
Let’s do a Punnett Square and consider a trait carried on the X chromosome (and when I say this, you may assume from this point that I’m talking about the differential region of the X, which is most of it) in humans. • Wild type = regular color vision (trichromatic) – C • Mutant = red/green color blindness (dichromatic) – c Because these are carried on the X, DON’T FORGET TO USE THE CHROMOSOMES THEMSELVES IN THE PUNNETT SQUARE. Like so…(those of you who missed lecture will have to figure this out on your own. boo hoo.) A few other interesting X-linked traits: • hemophilia (“Bleeding disease”) – traced back to Queen Victoria (recessive) • Androgen Insensitivity Syndrome (once called Testicular Feminization Syndrome) (recessive) – Next lecture, we’ll take a closer look.
