There is no aggressive gene that's been identified yet. Aggression is far to complex a matter to be dismissed as something genetic. If you're planning on keeping roosters at all then deal with this one. The constant round of kill and replace until one gets a 'good' one isn't the way forward.
Lots of posts on this forum and others talking about aggressive roosters. It's not until page whatever you find out the behaviour the poster is describing isn't actually aggressive at all.
This article will help you decide if his behaviour is in reality full out aggression or something else.
In general my advice to anyone with children involved in chicken keeping who get to such a point they are seeking opinions on a forum about roosters is to get rid of the one they have and
don't get any more.
https://www.backyardchickens.com/articles/understanding-your-rooster.75056/