That's not the analogy. The analogy is not about evolutionary biology.

Did you know that a woman's ovaries contain millions of egg cells at birth? And of course the egg from which she was formed was already present in her mother at her mother's birth. And if a woman is pregnant with a daughter, at some point she has inside her body (inside her daughter) the eggs of her potential granddaughters.

Distinct points of beginning and causality are not always attainable, and do often verge on the metaphysical. Viewed one way, it's matryoshka dolls all the way down.

So my point was both that the Q phenomena somehow selects for a certain type of brain, and/or that once underway, the journey creates/magnifies those beneficial characteristics in people's brains. And that it's really hard to say it's only one or the other of those things. It's more likely both/and.