highly significantp ≈ 5.0 × 10 −5
In addition, to mitigate potential impacts of small expected counts (e.g., expected values < 5 for TPS-c) on the chi-square approximation, a permutation test (20,000 permutations) was performed and also yielded a highly significant result ( p ≈ 5.0 × 10 −5 ), further supporting that the distribution of core/non-core status varies significantly among subfamilies.