A. Domain architecture conservation across all species for pairs of orthologs and closest cross-species outparalogs. DA-score is averaged within ranges (bins) of sequence divergence. The scores for each pair category were first averaged within each cluster so that each cluster contributes equally to the average scores regardless of size. Ortholog pairs have greater domain architecture conservation than outparalog pairs of equivalent sequence divergence, at least when sequence divergence is high. Error bars show the standard error of the means for each pair category. The triangle markers indicate significant (Bonferroni corrected p < 0.05) difference between the category means within each bin. In these plots, the data was divided into 50 bins. B. The equivalent analysis for pairs of inparalogs and same-species outparalogs. Inparalog pairs in this context are proteins within the same species (human or a model organism) that diverged after the speciation event, whereas outparalog pairs are proteins within the same species that diverged before the speciation event. Both types of pairs are paralogs, and they behave similarly as sequence divergence increases. C. The equivalent analysis for pairs of orthologs and inparalogs. Just as seen in A, mean DA-score falls significantly more quickly for paralogs than for orthologs as sequence divergence increases.