So x uppercase by, and these two are basically colorblind. So x lowercase b y and x lowercase by. So we see that by making the assumption that our trait, in this case, it's our colorblind trait, by making the assumption it's sex link recessive, we are able to basically use the information given to us in the pedigree. And we were able to correlate this information with information that was obtained from these pundits square experiments. That is, this information given to us from the sex link recessive assumption was consistent with the pedigree information that we began with. And initially we saw that it couldn't be autosomal recessive because the information given to us from this pound square was not consistent with information given to us in this section of our pedigree.