相关性分析:完整技术报告

主要发现:检验了 30,651,241 对基因-代谢物,187,640 对通过主筛选,其中组内也成立的 Tier1 只有 99 对(0.1%):绝大多数高相关来自组间差异。

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1 分析目的

在分子层面找出表达量与代谢物含量共同变化的基因-代谢物对,是构建网络、九象限和调控假设的基础。由于跨处理、跨水平的组间差异会让大量本无直接关系的分子同时变化,本分析同时计算组内相关,把“只因组间差异而相关”的配对与“组内个体之间也相关”的配对分开。

2 分析原理

全样本相关 r_all:30 个样本上的 Pearson 相关。代谢物未检出的样本不参与该代谢物的计算;检出少于 12 个样本的代谢物不检验。显著性:t = r·√[df/(1−r²)],df = n − 2(n 为实际参与的样本数),双侧 P;对全部基因 × 代谢物配对做 BH 校正得到 fdr_all。

组内相关 r_within:每个分子在每组内减去组均值,对残差求 Pearson 相关,等价于以“分组”为协变量的偏相关;df = n − g − 1(g 为参与的组数)。它扣除了处理和水平造成的共同变化,只反映组内个体差异的共变。组内只有 1 个检出值的组不提供组内信息。

证据分级:主筛选为 |r_all|≥0.8 且 fdr_all<0.05。通过主筛选后,若组内相关 fdr_within<0.05 且与 r_all 同号,记为 Tier1;否则记为 Tier2。

逐比较:每个比较只取该比较的差异基因 × 差异代谢物,沿用 30 样本的 r_all 和 r_within,FDR 在该比较的配对内重新校正;另给出只用该比较 6 个样本的 r_cmp 作对照。为什么不用 6 样本相关作主要依据:6 个样本分两组,差异分子天然呈“两团”分布,几乎都能得到 |r|>0.8,没有区分度。

3 输入数据及预处理

基因:表达过滤后的基因 ∪ 任一比较的差异基因,log2(FPKM+1)。代谢物:全部有变异的代谢物,log2 强度,未检出为 NA。30 个样本。

4 软件、算法及参数

软件 / 函数版本用途与关键参数
R4.4.3矩阵相关(中心化后矩阵乘法,与 stats::cor 一致)、t 分布 P、p.adjust(BH)
data.table1.18.6.1长表整理

5 统计指标解释

下表列出本页出现的全部统计指标和缩写(由页面内容自动生成)。全部术语见术语表。

术语中文名英文名定义与读法
FPKM每千碱基每百万片段数Fragments Per Kilobase of transcript per Million mapped fragments转录组表达量单位,按基因长度和测序深度归一化。本流程用 log2(FPKM+1) 作为基因表达值。
log2FC以 2 为底的倍数变化对数log2 fold change两组均值之比取 log2。本报告统一为 log2(后一组/前一组),比较名 A_vs_B 中 B 为后一组;log2FC=1 表示后一组是前一组的 2 倍,-1 表示一半。基因的 log2FC 来自服务商 DESeq2 结果;代谢物为两组原始强度均值之比。两组都未检出时没有 log2FC(记为 NA,不是 0)。
PP 值P value在原假设(无差异、无相关或无富集)成立时,得到当前或更极端结果的概率,未经多重检验校正。
FDR错误发现率false discovery rate多重检验校正指标,表示在所有判为显著的结果中,预期假阳性所占比例。本报告全部用 Benjamini–Hochberg 方法计算,检验范围在各分析中分别说明(如“该比较的全部配对”“全部可评估通路”)。
BHBenjamini–Hochberg 校正Benjamini–Hochberg procedure把 m 个 P 值从小到大排序,第 i 个的校正值为 min(1, min_{k≥i} P_(k)·m/k)。控制 FDR,比 Bonferroni 校正宽松。
NA缺失值not available没有数值。未检出、未检验或不可计算时记为 NA,不当作 0。
r相关系数correlation coefficient本报告中未特别说明时指 Pearson 积矩相关系数,范围 −1 到 1;正值表示同涨同落,负值表示此消彼长,绝对值越大线性关系越强。
Pearson皮尔逊相关Pearson correlationr = Σ(x−x̄)(y−ȳ) / √[Σ(x−x̄)²·Σ(y−ȳ)²],衡量线性关系。显著性用 t = r·√[df/(1−r²)] 服从自由度 df 的 t 分布检验。
r_all全样本相关correlation across all samples30 个样本上的 Pearson r(代谢物未检出的样本不参与),包含组间差异和组内个体差异两部分。
r_within组内相关within-group correlation每个分子先减去所在组(10 组)的组均值,再对残差求 Pearson r。它只反映组内个体之间的共变,等价于以分组为协变量的偏相关。自由度 = 样本数 − 组数 − 1。
r_cmp比较内相关correlation within one comparison只用该比较的 6 个样本计算的 Pearson r,6 样本中有未检出时记为 NA,只作对照。
fdr_all全样本相关的 FDRFDR of r_allr_all 的 BH 校正 P;全局分析在全部已检验配对内校正,逐比较在该比较的差异基因 × 差异代谢物配对内校正。
fdr_within组内相关(或组内耦合)的 FDRFDR of within-group correlation组内相关 P 值的 BH 校正值;通路活性页为组内置换 P 在全部可评估通路内的 BH 校正值。
df自由度degrees of freedom相关检验中为 n−2(n 为参与计算的样本数);组内相关为 n − 组数 − 1。
Tier1一级证据配对Tier 1 pair|r_all|≥0.8 且 FDR<0.05,同时组内相关 FDR<0.05 且与 r_all 同号。说明两者的关联在扣除组间差异后仍存在。
Tier2二级证据配对Tier 2 pair只满足 |r_all|≥0.8 且 FDR<0.05,组内相关不显著或方向不同,关联可能主要来自组间差异。
PC主成分principal componentPCA 得到的新坐标轴,PC1 解释的方差最多。
KEGG京都基因与基因组百科全书Kyoto Encyclopedia of Genes and Genomes代谢通路和分子功能数据库。本流程用 KEGG 通路、KO、化合物(C 编号)和反应(R 编号)注释。
TF转录因子transcription factor结合 DNA 调控其他基因转录的蛋白。本流程按服务商注释的 TF 家族识别。

6 图表与结果展示

全局结果

全局高相关配对 全部基因×代谢物 r 矩阵

全局高相关配对(Tier1 在前)预览前 200 行,共 187,640 行下载全表

表注:gene、met 为基因和代谢物编号;r_all、fdr_all 为 30 样本相关和 FDR(在全部已检验配对内 BH 校正);r_within、fdr_within 为组内相关和 FDR;n_detected 为代谢物检出样本数(参与计算的样本数);tier 为证据等级。

genemetr_allfdr_allr_withinfdr_withinn_detectedtier
MSTRG.41858.3POS_t66-0.99373.89e-11-0.98650.0180316Tier1
Ac_DH066619_chr7_03967POS_t1360.97311.24e-140.90750.017230Tier1
MSTRG.6027.1POS_t66-0.96665.05e-07-0.98120.0298516Tier1
Ac_DH066619_chr7_03021POS_t1360.96412.17e-130.86260.0488430Tier1
MSTRG.40803.10POS_t1360.95811.05e-120.88470.0298530Tier1
MSTRG.67323.7POS_t66-0.95632.28e-06-0.98650.0180316Tier1
Ac_DH066619_chr7_02810POS_t1360.9533.46e-120.95940.00020830Tier1
Ac_DH066619_chr7_03675POS_t1360.94044.48e-110.94630.00093230Tier1
Ac_DH066619_chr4_00337NEG_q240-0.93251.73e-10-0.91830.0102230Tier1
Ac_DH066619_chr6_03591POS_q2510.92644.42e-100.87150.0407530Tier1
Ac_DH066619_chr4_03039NEG_t204-0.92555.09e-10-0.87180.0407530Tier1
Ac_DH066619_chr5_00563POS_t150-0.91532.09e-09-0.87330.0391230Tier1
Ac_DH066619_chr4_03039POS_t140-0.91512.15e-09-0.8950.0228430Tier1
Ac_DH066619_chr6_00094POS_q386-0.91113.57e-09-0.9480.00093230Tier1
Ac_DH066619_chr7_02819NEG_q240-0.90775.38e-09-0.89450.0228430Tier1
Ac_DH066619_chr1_06011NEG_t78-0.90487.58e-09-0.88070.0348930Tier1
Ac_DH066619_chr2_00866POS_q384-0.90269.72e-09-0.9060.017230Tier1
Ac_DH066619_chr5_05136NEG_q3100.89611.71e-050.97550.02720Tier1
Ac_DH066619_chr3_05318POS_q108-0.89292.76e-08-0.86340.0488430Tier1
Ac_DH066619_chr2_00866POS_t140-0.89153.18e-08-0.8620.0494130Tier1
Ac_DH066619_chr4_03039NEG_t155-0.88993.74e-08-0.89140.0254130Tier1
Ac_DH066619_chr1_03965POS_t1350.8894.07e-080.90190.0180330Tier1
Ac_DH066619_chr4_03039POS_q384-0.88774.63e-08-0.88920.0272730Tier1
Ac_DH066619_chr5_03686POS_q301-0.88714.93e-08-0.86930.0432430Tier1
Ac_DH066619_chr5_03686POS_q245-0.88486.15e-08-0.89510.0228430Tier1
Ac_DH066619_chr4_03039POS_t205-0.88217.93e-08-0.89490.0228430Tier1
Ac_DH066619_chr3_00736NEG_t95-0.8828e-08-0.89120.0255230Tier1
Ac_DH066619_chr7_02768NEG_q50-0.88019.46e-08-0.87910.0349730Tier1
Ac_DH066619_chr1_03965POS_t2350.8791.05e-070.89270.0242730Tier1
Ac_DH066619_chr7_02819POS_q386-0.87821.12e-07-0.93440.00255530Tier1
Ac_DH066619_chr4_00337NEG_t95-0.87651.3e-07-0.89870.0200730Tier1
Ac_DH066619_chr5_03686POS_t271-0.87521.46e-07-0.86850.0437230Tier1
Ac_DH066619_chr7_02819NEG_t95-0.87381.66e-07-0.87060.041430Tier1
Ac_DH066619_chr7_03680POS_t1360.87371.67e-070.88470.0298530Tier1
Ac_DH066619_chr3_00736NEG_q240-0.87351.7e-07-0.86680.0452430Tier1
Ac_DH066619_chr8_00121POS_t66-0.87280.000607-0.98650.0180316Tier1
Ac_DH066619_chr7_02768NEG_q266-0.87122.07e-07-0.88350.0308730Tier1
Ac_DH066619_chr5_03686NEG_t169-0.87072.14e-07-0.86910.0433430Tier1
Ac_DH066619_chr7_02819POS_q364-0.87072.15e-07-0.89940.0200230Tier1
Ac_DH066619_chr6_00764POS_q386-0.86852.59e-07-0.91440.0109430Tier1
Ac_DH066619_chr2_00866NEG_t155-0.86832.62e-07-0.87290.0391230Tier1
Ac_DH066619_chr7_02818POS_t26-0.86832.63e-07-0.86910.0433430Tier1
Ac_DH066619_chr4_03039POS_q385-0.86772.76e-07-0.88570.0295730Tier1
Ac_DH066619_chr4_03039POS_q229-0.86712.89e-07-0.87850.0350730Tier1
Ac_DH066619_chr8_02108NEG_q78-0.86672.98e-07-0.86850.0437230Tier1
Ac_DH066619_chr4_00720NEG_t780.86623.13e-070.87040.0415630Tier1
Ac_DH066619_chr7_02818NEG_t78-0.8663.16e-07-0.86790.0438830Tier1
Ac_DH066619_chr6_00764POS_t26-0.86593.2e-07-0.87640.0365730Tier1
Ac_DH066619_chr1_03965POS_t2020.86443.6e-070.88060.0348930Tier1
Ac_DH066619_chr7_02768NEG_t236-0.86373.8e-07-0.86210.0492830Tier1
Ac_DH066619_chr6_02781NEG_q240-0.86114.66e-07-0.86230.0491630Tier1
Ac_DH066619_chr6_04189NEG_q240-0.86074.82e-07-0.86850.0437230Tier1
Ac_DH066619_chr3_03799POS_t135-0.85985.16e-07-0.86660.0453230Tier1
MSTRG.11269.2POS_t26-0.85915.43e-07-0.86380.0486530Tier1
Ac_DH066619_chr7_02819POS_t26-0.85835.77e-07-0.88680.0282730Tier1
Ac_DH066619_chr7_02818NEG_t160-0.85786.01e-07-0.87040.0415630Tier1
Ac_DH066619_chr2_04998NEG_t78-0.85517.34e-07-0.86850.0437230Tier1
Ac_DH066619_chr2_00884POS_q386-0.85497.41e-07-0.89240.0242730Tier1
Ac_DH066619_chr3_00736POS_t26-0.85388.07e-07-0.88810.0276430Tier1
Ac_DH066619_chr1_03965POS_t70.85348.29e-070.89890.0200330Tier1
Ac_DH066619_chr1_03965POS_t580.84991.07e-060.88980.027130Tier1
Ac_DH066619_chr7_02818POS_q386-0.84621.38e-06-0.88760.0282730Tier1
Ac_DH066619_chr4_02817POS_q1730.84521.47e-060.86260.0488430Tier1
Ac_DH066619_chr7_02768POS_t140-0.8451.49e-06-0.88970.027130Tier1
Ac_DH066619_chr4_00337POS_t26-0.84471.53e-06-0.8770.0362230Tier1
Ac_DH066619_chr5_04987POS_t136-0.8431.71e-06-0.87460.0382630Tier1
Ac_DH066619_chr1_03965POS_t830.84281.73e-060.89960.0200230Tier1
Ac_DH066619_chr5_03686POS_t225-0.84141.9e-06-0.86840.0437330Tier1
Ac_DH066619_chr6_02781NEG_t95-0.84081.97e-06-0.88230.0326530Tier1
Ac_DH066619_chr6_00764NEG_t160-0.84052.01e-06-0.88480.0298530Tier1
Ac_DH066619_chr7_02768POS_q15-0.83932.18e-06-0.86530.0462730Tier1
Ac_DH066619_chr6_01226NEG_q240-0.8382.36e-06-0.87990.0348930Tier1
Ac_DH066619_chr5_03628POS_t26-0.83772.41e-06-0.87850.0350730Tier1
Ac_DH066619_chr8_00142POS_q426-0.83642.62e-06-0.86650.0453230Tier1
Ac_DH066619_chr6_02781POS_t26-0.82914.13e-06-0.89760.0208130Tier1
Ac_DH066619_chr4_03039NEG_t228-0.82724.64e-06-0.90190.0180330Tier1
Ac_DH066619_chr4_00337POS_q364-0.82694.71e-06-0.90560.017230Tier1
Ac_DH066619_chr3_03799POS_t235-0.82535.16e-06-0.88260.0321730Tier1
Ac_DH066619_chr4_00720NEG_t2280.82495.29e-060.86180.0495630Tier1
Ac_DH066619_chr3_03799POS_t83-0.82425.54e-06-0.86420.0479830Tier1
Ac_DH066619_chr6_00907POS_q385-0.8226.27e-06-0.88670.0282730Tier1
Ac_DH066619_chr6_00907POS_q384-0.82196.32e-06-0.8640.0482830Tier1
Ac_DH066619_chr7_02768NEG_t155-0.82136.53e-06-0.88410.0303930Tier1
Ac_DH066619_chr2_04998POS_t26-0.82126.58e-06-0.86990.0423530Tier1
Ac_DH066619_chr7_03876POS_t26-0.81598.82e-06-0.87720.0361630Tier1
Ac_DH066619_chr2_05147POS_t26-0.81568.99e-06-0.86190.0494330Tier1
Ac_DH066619_chr3_03799POS_t7-0.81529.18e-06-0.87290.0391230Tier1
Ac_DH066619_chr7_02768POS_t205-0.81499.32e-06-0.89450.0228430Tier1
Ac_DH066619_chr6_00094NEG_t160-0.81061.17e-05-0.86260.0488430Tier1
Ac_DH066619_chr5_04822NEG_q282-0.80921.26e-05-0.86560.0455630Tier1
Ac_DH066619_chr4_00629POS_t166-0.8091.28e-05-0.86770.0438830Tier1
Ac_DH066619_chr5_03628POS_q364-0.80791.35e-05-0.89450.0228430Tier1
Ac_DH066619_chr6_04189POS_t26-0.8071.42e-05-0.8850.0298530Tier1
Ac_DH066619_chr8_02695NEG_t2270.80651.46e-050.90520.017230Tier1
Ac_DH066619_chr1_02556POS_t2350.80631.47e-050.86290.0488430Tier1
Ac_DH066619_chr2_04534POS_t66-0.80480.004503-0.98650.0180316Tier1
Ac_DH066619_chr3_00073NEG_t810.80471.6e-050.86230.0491630Tier1
Ac_DH066619_chr7_03876POS_q364-0.80381.67e-05-0.87530.0374630Tier1
Ac_DH066619_chr6_02781POS_q364-0.80311.73e-05-0.86240.0491630Tier1
Ac_DH066619_chr3_05303NEG_t100.99184.4e-190.83270.0689230Tier2
Ac_DH066619_chr2_03323NEG_t100.9918.24e-190.011390.994730Tier2
Ac_DH066619_chr8_03073NEG_t10-0.99051.18e-18-0.65040.20130Tier2
Ac_DH066619_chr7_04135POS_q1810.99021.35e-180.84380.062730Tier2
Ac_DH066619_chr5_02963NEG_t10-0.991.35e-18-0.016850.99230Tier2
Ac_DH066619_chr4_00461NEG_t174-0.98951.34e-12-0.8120.198420Tier2
Ac_DH066619_chr6_03520NEG_t10-0.98913.51e-180.019210.990830Tier2
Ac_DH066619_chr5_05140NEG_t10-0.9893.51e-18-0.044350.97730Tier2
Ac_DH066619_chr5_05139NEG_t10-0.98893.51e-18-0.01150.994730Tier2
Ac_DH066619_chr6_00432NEG_t100.98893.51e-180.20050.845730Tier2
MSTRG.60526.2NEG_t100.98864.54e-180.44310.507930Tier2
Ac_DH066619_chr4_00461NEG_t10-0.98835.49e-18-0.24550.793830Tier2
Ac_DH066619_chr7_04135POS_q2510.9887.69e-180.59260.273830Tier2
Ac_DH066619_chr5_05116NEG_t10-0.98797.71e-180.0190.990930Tier2
Ac_DH066619_chr7_03613NEG_t100.98787.71e-18-0.10650.934130Tier2
Ac_DH066619_chr1_02289NEG_t10-0.98769.13e-180.020180.990330Tier2
Ac_DH066619_chr6_00537POS_q2510.98769.13e-180.64380.208730Tier2
Ac_DH066619_chr5_00170NEG_t10-0.98741.07e-17-0.018810.99130Tier2
Ac_DH066619_chr2_01769NEG_q2410.98731.14e-170.29050.736530Tier2
Ac_DH066619_chr2_00548NEG_t10-0.98711.3e-170.0073130.996630Tier2
Ac_DH066619_chr6_02623NEG_t100.98671.81e-17-0.13540.909830Tier2
Ac_DH066619_chr7_04007NEG_t100.98671.81e-17-0.24460.794930Tier2
Ac_DH066619_chr2_01769NEG_t10-0.98661.84e-17-0.053250.971630Tier2
Ac_DH066619_chr1_04254NEG_t100.98661.84e-170.058720.968230Tier2
Ac_DH066619_chr2_01775NEG_t10-0.98632.26e-17-0.066130.963430Tier2
Ac_DH066619_chr6_00537POS_q1810.98632.35e-170.83930.0648930Tier2
Ac_DH066619_chr6_00537NEG_t100.98612.59e-170.05550.970230Tier2
Ac_DH066619_chr7_04135POS_t1980.98612.64e-170.61270.246730Tier2
Ac_DH066619_chr8_02973NEG_t10-0.98593.11e-170.079710.954130Tier2
Ac_DH066619_chr5_02398NEG_t100.98583.19e-17-0.10140.938130Tier2
Ac_DH066619_chr5_00170NEG_q2410.98563.54e-170.13830.907330Tier2
Ac_DH066619_chr2_01775NEG_q2410.98563.54e-170.26530.769330Tier2
MSTRG.61600.1NEG_t100.98563.54e-170.46690.468930Tier2
Ac_DH066619_chr4_02530NEG_t10-0.98553.54e-17-0.023730.988530Tier2
Ac_DH066619_chr2_02194NEG_t10-0.98553.54e-170.018520.991130Tier2
MSTRG.14662.21NEG_q2410.98553.54e-170.40990.560830Tier2
Ac_DH066619_chr5_02963NEG_q2410.98543.72e-17-0.13970.90630Tier2
Ac_DH066619_chr4_01793NEG_t10-0.98543.8e-17-0.019370.990730Tier2
Ac_DH066619_chr5_03223NEG_t100.98533.95e-170.16450.882930Tier2
Ac_DH066619_chr6_01093NEG_t174-0.98531.45e-11-0.34450.787520Tier2
Ac_DH066619_chr4_04720NEG_q2410.98524.04e-170.19360.853230Tier2
MSTRG.14662.21NEG_t10-0.98524.04e-17-0.047720.97530Tier2
Ac_DH066619_chr1_02289NEG_q2410.98514.39e-170.077310.955830Tier2
Ac_DH066619_chr7_00031NEG_t10-0.98514.46e-17-0.02630.987130Tier2
Ac_DH066619_chr5_00152NEG_t10-0.9854.46e-170.040230.979430Tier2
Ac_DH066619_chr5_05139NEG_q2410.9854.59e-17-0.15370.893230Tier2
Ac_DH066619_chr3_03659NEG_t100.98494.93e-17-0.33560.673830Tier2
Ac_DH066619_chr8_02472NEG_t174-0.98491.74e-11-0.20860.896320Tier2
Ac_DH066619_chr4_01793NEG_t174-0.98491.75e-110.20860.896320Tier2
MSTRG.7657.6NEG_t174-0.98481.81e-110.20860.896320Tier2
Ac_DH066619_chr3_05293NEG_t10-0.98475.73e-17-0.024320.988130Tier2
Ac_DH066619_chr3_05298NEG_t100.98475.73e-17-0.058380.968430Tier2
Ac_DH066619_chr5_05128NEG_t10-0.98475.73e-17-0.0081830.996230Tier2
Ac_DH066619_chr2_01446NEG_t10-0.98465.82e-17-0.04580.976130Tier2
Ac_DH066619_chr2_02194NEG_t174-0.98452.08e-110.20860.896320Tier2
Ac_DH066619_chr5_05133NEG_t174-0.98452.11e-110.011370.996220Tier2
Ac_DH066619_chr2_02383NEG_t10-0.98456.58e-17-0.03560.98230Tier2
Ac_DH066619_chr5_05140NEG_q2410.98446.68e-17-0.17890.868530Tier2
Ac_DH066619_chr2_02837NEG_t10-0.98446.68e-17-0.18880.858330Tier2
Ac_DH066619_chr5_00129NEG_t10-0.98446.68e-17-0.047260.975330Tier2
Ac_DH066619_chr2_02568NEG_t10-0.98446.68e-170.032040.98430Tier2
MSTRG.33964.3NEG_t174-0.98432.33e-11-0.20860.896320Tier2
Ac_DH066619_chr7_04135NEG_t100.98427.18e-170.13240.912530Tier2
Ac_DH066619_chr2_00548NEG_q2410.98417.73e-170.067120.962730Tier2
Ac_DH066619_chr8_01497NEG_q2410.98418.12e-170.19210.854830Tier2
Ac_DH066619_chr6_03520NEG_t174-0.98412.55e-11-0.20860.896320Tier2
Ac_DH066619_chr4_00461NEG_q2410.9848.19e-17-0.17380.873730Tier2
Ac_DH066619_chr6_03520NEG_q2410.9848.67e-17-0.37820.610430Tier2
Ac_DH066619_chr5_02398POS_q2510.98399.21e-170.29260.733530Tier2
MSTRG.7210.77POS_q2510.98389.52e-170.60760.253530Tier2
Ac_DH066619_chr3_00062NEG_t174-0.98372.91e-11-0.054720.9820Tier2
Ac_DH066619_chr8_02973NEG_t186-0.98371.04e-16-0.60030.263230Tier2
Ac_DH066619_chr1_04259POS_q2510.98371.04e-160.72720.130130Tier2
Ac_DH066619_chr2_03356NEG_t174-0.98363.06e-110.20860.896320Tier2
Ac_DH066619_chr6_01673NEG_t10-0.98361.08e-160.043790.977330Tier2
Ac_DH066619_chr7_00032NEG_t10-0.98361.08e-16-0.011510.994630Tier2
Ac_DH066619_chr1_03145POS_q1810.98351.1e-160.73850.122330Tier2
Ac_DH066619_chr7_03613POS_q2510.98351.1e-160.26920.764330Tier2
MSTRG.321.2NEG_t100.98341.16e-16-0.29880.725230Tier2
MSTRG.38159.1NEG_t174-0.98343.34e-11-0.24860.867820Tier2
Ac_DH066619_chr4_02421NEG_t10-0.98341.18e-160.031190.984430Tier2
Ac_DH066619_chr6_00537POS_t2130.98341.18e-160.56910.307230Tier2
Ac_DH066619_chr6_01019POS_q251-0.98341.2e-16-0.5530.331730Tier2
Ac_DH066619_chr1_03145POS_t1980.98331.23e-160.59420.271630Tier2
MSTRG.10832.1POS_t1980.98311.41e-160.8070.0800730Tier2
Ac_DH066619_chr7_03649POS_q2510.98311.41e-160.55780.324330Tier2
Ac_DH066619_chr8_01509NEG_q2410.98311.41e-160.3340.676130Tier2
Ac_DH066619_chr4_04720NEG_t10-0.98311.42e-16-0.056060.969930Tier2
Ac_DH066619_chr6_00537POS_t1980.9831.47e-160.62120.23630Tier2
Ac_DH066619_chr4_01469NEG_t10-0.9831.47e-16-0.052090.972330Tier2
Ac_DH066619_chr1_03145POS_q2510.9831.47e-160.54880.33830Tier2
Ac_DH066619_chr2_02838NEG_t10-0.98291.57e-160.048780.974430Tier2
Ac_DH066619_chr6_01673NEG_t186-0.98281.6e-16-0.54880.33830Tier2
Ac_DH066619_chr5_00129NEG_t174-0.98284.39e-110.20860.896320Tier2
Ac_DH066619_chr3_05798NEG_t10-0.98271.74e-16-0.032530.983730Tier2
Ac_DH066619_chr7_04135POS_t2130.98271.76e-160.53590.35830Tier2
Ac_DH066619_chr4_04031NEG_t10-0.98271.76e-16-0.024230.988230Tier2
MSTRG.62505.1NEG_t100.98261.84e-16-0.26090.77530Tier2
Ac_DH066619_chr3_05398NEG_t174-0.98264.74e-11-0.11820.950420Tier2
Ac_DH066619_chr2_01788POS_q2510.98261.87e-160.30290.719730Tier2
Ac_DH066619_chr3_03374NEG_t10-0.98261.88e-16-0.018470.991130Tier2
各比较相关汇总共 45 行下载全表

表注:deg、dam 差异基因和差异代谢物数;pairs 检验的配对数(差异基因 × 差异代谢物);tier1、tier2 通过阈值的配对;not_tested 代谢物检出不足未检验的配对;pos、neg 通过阈值配对中正、负相关数;cmp_r08 只用 6 个样本时 |r|≥0.8 且 P<0.05 的配对数(对照)。

comparisoncategorydegdampairstier1tier2not_testedposnegcmp_r08
R1_vs_R2B_R组内跨水平99810000037
R1_vs_R3B_R组内跨水平310300000023
R1_vs_R4B_R组内跨水平21735812603401063048258132901
R1_vs_R5B_R组内跨水平5034653272103633124019841503123768
R1_vs_Y1A_同水平处理间2798752098501222337496761255896148
R1_vs_Y2D_跨水平跨处理2566842155441124358741142512944107992
R1_vs_Y3D_跨水平跨处理2837932638416327431091625816491136842
R1_vs_Y4D_跨水平跨处理391384328692421909737743311706147617
R1_vs_Y5D_跨水平跨处理5791142822322026574371177714797396789
R2_vs_R3B_R组内跨水平812960000046
R2_vs_R4B_R组内跨水平1909519735913736028346647568
R2_vs_R5B_R组内跨水平4561693147092903632019911931174020
R2_vs_Y1D_跨水平跨处理260277200354329111971314215972113902
R2_vs_Y2A_同水平处理间23891032460671533661971553318143141465
R2_vs_Y3D_跨水平跨处理26601193165403433301382079622537174108
R2_vs_Y4D_跨水平跨处理396598388570027678471134616332214432
R2_vs_Y5D_跨水平跨处理5683165937695033681471415819523561567
R3_vs_R4B_R组内跨水平32009931680002203010061197184801
R3_vs_R5B_R组内跨水平5456965237762675220029592528333803
R3_vs_Y1D_跨水平跨处理3348822745363309322971365817277151650
R3_vs_Y2D_跨水平跨处理28871083117964348702941607318801183285
R3_vs_Y3A_同水平处理间30431243773323449573532144623514219018
R3_vs_Y4D_跨水平跨处理46151346184105274142911093316486368556
R3_vs_Y5D_跨水平跨处理680120313806030344243381455619868882784
R4_vs_R5B_R组内跨水平1058353703001160872916534
R4_vs_Y1D_跨水平跨处理488519796234513764987773380942702555587
R4_vs_Y2D_跨水平跨处理4818209100696239787367683568443091553509
R4_vs_Y3D_跨水平跨处理4929237116817315916388964151950134712883
R4_vs_Y4A_同水平处理间422215063330015737678173123242550396302
R4_vs_Y5D_跨水平跨处理426322897196412785549593327845288670899
R5_vs_Y1D_跨水平跨处理6155178109559028845617713701147578626709
R5_vs_Y2D_跨水平跨处理6329204129111622893957623996449453723735
R5_vs_Y3D_跨水平跨处理63992361510164201000828914474255360917388
R5_vs_Y4D_跨水平跨处理59591619593998792498143329445963636643
R5_vs_Y5A_同水平处理间532523112300758885039563764450867851705
Y1_vs_Y2C_Y组内跨水平411440101030
Y1_vs_Y3C_Y组内跨水平251947500000182
Y1_vs_Y4C_Y组内跨水平12227692872137296011431935933
Y1_vs_Y5C_Y组内跨水平20861102294600712032139181394
Y2_vs_Y3C_Y组内跨水平312360000023
Y2_vs_Y4C_Y组内跨水平9741029934868350011430443780
Y2_vs_Y5C_Y组内跨水平23781062520685906040051191792
Y3_vs_Y4C_Y组内跨水平49910351397117803814123988
Y3_vs_Y5C_Y组内跨水平2349125293625111920506687125190
Y4_vs_Y5C_Y组内跨水平12043036120017801077115602

各比较结果

7 结果描述

检验范围。30,651,241 对基因-代谢物完成检验;另有 26,572 对因代谢物检出不足 12 个样本而未检验。

主筛选与分级。|r_all|≥0.8 且 FDR<0.05 的配对共 187,640 对,其中负相关占 54.1%。这些配对的组内相关有 65.8% 绝对值小于 0.3;组内也显著且同向的 Tier1 为 99 对,涉及 48 个基因和 43 个代谢物。

代谢物类别。高相关配对最多的类别是 Flavonoids(53,444 对),其次是 Sugars(40,696 对)。

逐比较。各比较的 Tier1 配对数中位数为 4,最多的是 R1_vs_R5(363 对);5 个比较没有通过阈值的配对。只用 6 个样本计算时,|r|≥0.8 且 P<0.05 的配对中位数为 147,617,说明 6 样本相关缺乏区分度。

8 生物学意义

数据支持的观察

处理和水平造成的大规模组间差异,使成千上万个基因与代谢物“同涨同落”,这类相关不能区分直接的代谢联系和间接的共同响应。扣除组间差异后仍成立的 Tier1 配对数量很少,它们在同一处理水平的个体之间也协同变化,是更接近直接关联的候选。

需要进一步验证的假设

Tier1 配对中的基因可能参与该代谢物的合成、转化或转运,也可能与之受同一上游信号调控。需要结合 KEGG 已知反应(“已知反应配对”页)筛选有生化依据的配对,再用基因表达干预(过表达、敲除)和代谢物测定验证。

9 局限性

相关只说明共变,不说明因果或直接调控。r_all 混合了组间和组内两种来源,Tier2 配对很可能只是“都随处理或水平变化”。组内相关的自由度只有约 19,检验功效低,Tier1 少不代表没有真实关系。检验了约 3 千万对,即使 FDR 控制在 5%,假阳性的绝对数也不小。Pearson 对离群值敏感。

参考文献

  1. Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistical Society Series B, 1995, 57(1): 289–300.
  2. Cavill R, Jennen D, Kleinjans J, Briedé JJ. Transcriptomic and metabolomic data integration. Briefings in Bioinformatics, 2016, 17(5): 891–901.