Cloning Mutated Creatures
Cloning a mutated creature copies all the existing mutations

This interaction has been put together by a modification of the first layer of continuous effect interactions and two new rules.


  613.1a Layer 1: Rules and effects that modify copiable values are applied.


Previously, this layer applied 'copy effects'.  Now it's been generalized to apply 'copiable values', of which includes the newly created category of "merged permanents"


  721.2a A merged permanent has only the characteristics of its topmost component, unless otherwise specified by the effect that caused them to merge. This is a copiable effect whose timestamp is the time the objects merged. (See rule 613.2.)


And mutate, the effect causing the permanents to merge, modifies the characteristics to include the rules text of the other objects.


  702.139e A mutated permanent has all abilities of each card and token that represents it. Its other characteristics are derived from the topmost card or token.