DNA Tweaks other Deluxe Item help

Do these only ADD a gene trait?  Or can they remove them too?  I want to be able to remove the grey gene from my one really awesome stallion, and maybe a mare.

Do these tweaks change the DNA or only the appearance?  For example, if I do a Coat Applicator on a horse, does that also have an effect on the genes, or appearance only?  I want to find this out BEFORE spending the points on it.

Applicators add and remove genes. For example the Grey applicator will give the option of changing the grey slot to GG, Gg or gg, as will other gene tweaks. 

All colour changing items while change the horse genetics as well as the colour, with the exception of Freeze Grey, which only keeps the shade of grey currently displayed on the horse image. 

tweaks change the DNA as well as the appearance.

you can add and remove colors/patterns. using a grey tweak on a grey horse will allow you to remove their grey gene. there is an item called Freeze Grey that only affects appearance of grey, but does not change the DNA