Regarding the PNAS paper titled Genomic analysis of the hierarchical structure of regulatory networks, I am having trouble understanding the organization of the columns. How was the placement of proteins in columns determined? And what is the purpose behind the duplication of level 1 proteins such as SPT8, and gaps within the columns?
Unfortunately, I think that is a typo when PNAS edited our paper. It is not in our pdf file that we sent to PNAS.