Hi, what is Berkserker (Ancient) ?  I know about the regular version of  it, but I just saw this one.

Is it a old deleted version?

At the beginning of the game, dragons used to have Berserker in their gene pool. It turns out this was a mistake, so the gene will not appear in wild dragons you catch now, nor can it be inherited from older dragons who have it. The gene was removed because dragons already have Boiling Blood, which has a similar function to Berserker.

Adding on to Sumatra_Echo's answer, the ancient gene will only appear in offspring if they have two pairs of it.