A closer look
When an isolated group aggressively interbreeds for too long, their genetic diversity tanks and their molecular instructions become dangerously stagnant. Luckily, occasionally someone physically wanders in from completely outside the group and starts mixing their distinctly different sequences into the local pool. This abrupt introduction of foreign instructions dramatically shakes up the genome, breaking up the stagnant traits and giving the local population a fighting chance at long-term survival.
