I've come across some people arguing to use bee swarms, rather than to buy queen bees. The argument was that, bee swarms have grown strong enough to be able to split off and adapt to one's local environment, whereas queens are often enough not suitable for such and tend to under perform in comparison.
At least here in my part of Australia, people like buying queen bees from the local bee sanctuary, Kangaroo Island, which houses a pure strain of Ligurian Bee.
Now I'm wanting to split a number of my hives to expand my operation. I have one hive that's probably the most productive of the lot (could just be because it's the oldest most established), and it's also by far the most aggressive hive. I figure that, in spite of how productive they are, I don't wish to duplicate such aggressive bees and if anything, I should try to replace the queen with more gentler genetics. I've thought about finding the queen and squishing her, then take out all the frames that have eggs/young larvae in them, and replace them with eggs/young larvae from hives that have more desired traits. I figure I can do this with any beehive that has undesirable characteristics. A number of my hives don't ever seem to perform too well. It's difficult to tell if it's just due to their current circumstances, that they just need more time, or whether the genetics of the bees is not as strong.
This is all a pretty fascinating topic. How do you guys manage the genetics of your bees?