Over-represented words in the 1 kb upstream promoter regions were identified using the Element algorithm [41].

Group: Group of significantly over-represented words in the promoter regions; Words: No. of significant words in each group, words can be of different lengths; Known cis-elements: Words found in the previously known motifs.分组：启动子区域内显著富集的词组；词数量：每个分组中的显著词项数目，此类词项可具有不同长度；已知顺式作用元件（cis-elements）：已在既往已知基序中被发现的词项。