We carry out a straightforward analysis by counting how often the gene with the highest expression context conservation also has the highest sequence identity.
For those X-X orthologous groups with a negative correlation, we therefore checked if there was one gene pair that harbored both the highest expression context conservation and the highest sequence identity.
One contained the highest expression context correlation score in each 1 2 orthologous group (most conserved 1 2 orthologs, cf. Fig. 4), the other contained the lower scores (less conserved 1 2 orthologs).
We therefore sub-classify each X-X orthologous group into the gene pair that has the highest expression context conservation within this orthologous group on the one hand (we will refer to this gene pair as the "most conserved X-X orthologous gene pair"), and on the other hand the remaining, "less conserved X-X orthologs" (Fig. 4).
However, it is not clear whether the ligand-independent HER dimerization only occurs in an oncogenic high ERBB expression context such as cancer cells with high HER2 expression, or it can occur in low HER2 expressing cell lines.
We find that all "Information storage and processing" categories have a higher level of expression context conservation than all "Metabolism" categories.
In our results, we also observe the highest correlation between expression context conservation and sequence identity for the 1-1 ofthologS.of S. cerevisiae and C. elegans, rather than for two closer related Metazoa.
This result revealed that the HMOX1c genetic variant that conferred increased risk to develop CM is also associated to higher expression of HMOX1 mRNA in the context of CM.
For each functional category, the fraction of 1-1 orthologenesgenes with an expression context conservation score higher than zero is shown in Fig. 3.
In this context, placentae from preeclamptic pregnancies have higher expression levels of AR in both male and female fetuses (Sathishkumar et al., 2012).
