A creature that adds an ability to a set of creatures (e. g. a Winged Sliver) is enchanted with Darksteel Mutation. Will the other creatures still have that ability?

I remember that Humility and Painter's Servant leads to creatures without abilities (including Painter's Servant) that nonetheless have the chosen color. The reason for this is that color-changing effects are applied in layer 5 and thus before abilities are removed in layer 6.

Applying that to the first case, layer 6 should be evaluated like this (time stamp order): First, all matching creatures gain the ability, then all abilities are removed only from the enchanted creature. In my example, all slivers would have flying except the enchanted Winged Sliver. Is that true?

Slivers will not have flying.

Since both effects act in the same layer (6 - adding and removing abilities), there can be dependency (dependency can only apply inside layers). Winged Sliver's effect depends on Darksteel Mutation's effect, since applying Darksteel Mutation changes what Winged Sliver does. So we apply the independent effect first - Darksteel Mutation - and then see what else is left to apply. In this case, nothing, since Winged Sliver has lost its ability.

Daniel Kitachewsky
L3, Paris, France
Rules NetRep