Uppercase B, uppercase B or uppercase B? Lowercase B and BB. So now, if we carry out this same experiment, what do we see? Well, let's suppose it's upper case B and this. So we see that if it was uppercase B, uppercase B, lowercase B, lowercase B, all of these must be uppercase B, lowercase B. And what that means is all of these must actually express that disease for the phenotype, for that disease, which is not true, which is not consistent with this pedigree, because all these have normal phenotype.