① 全部组合① All combinations
r² 0.2 面板有 59,704 个 SNP,两两组合共 1,782,253,956 对。逐对用正式模型检验太慢,所以先做快速初筛。The r² 0.2 panel has 59,704 SNPs, giving 1,782,253,956 pairs. Testing each with the full model is too slow, so a fast screen comes first.
② 快速初筛(PLINK)② Fast screen (PLINK)
PLINK 的 --epistasis 每秒约检验 1,000 万对,但不能加入亲缘项。所以先用零模型从现蕾时间中减去亲缘部分,在上初筛。p < 10⁻⁴ 的 54,158 对被写出。PLINK's --epistasis tests about 10 million pairs a second but cannot include kinship. A null model first removes the kinship part from time to buds, and the screen runs on the . The 54,158 pairs with p < 10⁻⁴ are written out.
③ 四格规则和秩检查③ Four-cell rule and rank check
写出的对中有 26% 不满足每格 ≥ 10 个品系。在残差上,品系很少的格子容易产生极端值。剩下的 40,288 对都通过了,即乘积项确实带来了新的信息。26% of the written pairs fail the ≥ 10 lines per cell rule; on residuals, cells with very few lines readily give extreme values. All 40,288 remaining pairs pass the , meaning the product term adds new information.
④ 预算:前 1,000 对④ Budget: the top 1,000
按初筛 p 值排序,只用正式模型复检前 1,000 对。预算决定计算量和漏检之间的平衡。在一个 500 个 SNP 的测试面板上,初筛与正式模型的排序相关系数为 0.985,正式模型的前 50 名都在初筛的前 1,000 名之内。Pairs are sorted by screening p-value and only the top 1,000 are re-tested with the full model. The budget sets the balance between computing and misses. On a 500-SNP test panel, screen and full-model rankings correlate at 0.985, and the full model's top 50 all fall within the screen's top 1,000.
⑤ 门槛:工作口径下 0 对⑤ The bar: 0 pairs in the working setting
门槛为 2.9 × 10⁻¹¹。最接近的一对在工作口径(固定方差比)下 p = 5.2 × 10⁻¹¹,没有越过。逐对重估方差比后 p = 9.0 × 10⁻¹⁴,越过了门槛。但它的信号来自一个只有 13 个品系的格子,其中 6 个来自意大利;后 p = 1.3 × 10⁻⁸,品系后最差 p = 3.8 × 10⁻⁹,都明显变弱。它属于在敏感性分析下过阈值、稳健性存疑的探索性候选。是否把稳健性作为发现的附加条件,待导师讨论。下一节可以查看这一对。The bar is 2.9 × 10⁻¹¹. Under the working setting (fixed variance ratio) the closest pair has p = 5.2 × 10⁻¹¹ and does not clear it. With a per-pair variance ratio, p = 9.0 × 10⁻¹⁴, which does. But the signal comes from a cell of only 13 lines, 6 of them from Italy, and it weakens clearly after (p = 1.3 × 10⁻⁸) and (worst p = 3.8 × 10⁻⁹). It is an exploratory candidate that clears the bar in a sensitivity analysis but has doubtful robustness. Whether robustness should be a condition for a finding is open for discussion with the supervisor. The next section shows this pair.