Females heterozygous for X linked diseases

[kysa]

I know that female mammalians randomly inactivate one X chromosome in somatic cells.So, if a human female was daltonism carrier, would not she be half daltonic?Because, ~1/2 of her cells in retina would have a recessive allele and the other half would have the dominant allele?Or 1/2 is not enough to cause color blindness?And I'd like to know if it's true with other X linked diseases.

[JackBean]

First, the inactivation is done during embryogenesis and then is passed through during mitosis, so it would not be half cells, but probably either all or none.
However, I think it's not that simple. There should be some discussion about that here somewhere already. Try to search it.