respec and skill ups of talent powersFollow

I've been thinking of becoming a combat [iam a 41/20]. Or at least trying combat out.

And this made me realise that i didnt know something.

Mutilate is a talent given power. Lots of other classes have powers from talents. They have levels too that can be upgraded at a trainer.

So what iam getting at is. If i change to combat and then return to assasination. WIll i have to upgrade mutilate all the way again?

Do talent given powers switch back to level 1 when you de-spec and then return to them?