This item applies G to a colonist's genome via design update.
Greying appears in two different ways: The first is to desaturate and sometimes lighten across the entire body. The other way is to lighten (and sometimes desaturate) in large patches across the body, focusing on the face and the withers most commonly. Greying is a gene attached to aging, similar to how old dogs have white faces. There can be salt-and-pepper like dashes of greying, especially in longer-furred areas like the mane and cheek fluffs. This affects all markings, though there is no visual effect on white spotting markings.
Notice that just using the "desaturate" option on photoshop, etc, won't work: that darkens the grey to try to match the visual value. Greying lightens the coat so you should be around the same level of luminance as the coat it's on.
