We have explored the possible conservation of relationships between mRNA abundances and chromosomal organization in the highly reduced genome of Buchnera aphidicola, the primary endosymbiont of the aphids, and a close relative to Escherichia coli.
Similarly, Tdrd7 and Tdrd6 double-knockout mice exhibited more severe defects in chromatoid body and Miwi localization than single mutants [ 21, 42], suggesting a conservation of functional relationship among piRNA components across species.
In conclusion, the analysis of mRNA abundances with regard to chromosomal organization in Buchnera has shown, despite an important reduction in its genome size and an apparent decay of its transcriptional regulatory capacity, a conservation of the relationship between these two parameters in the aphid symbiont.
The distance used to construct the phylogeny in our strategy is a measure of the conservation of gene relationships between two organisms, which is completely different from the gene content method that is based on the conservation of shared genes (Figure S1, Table S5).
Based on the evolutionary conservation of gene relationships, we test the hypothesis that a seed network derived from studies of retinal cell determination in the fly, Drosophila melanogaster, will be an effective way to identify novel candidate genes for their role in mouse retinal development.
However, conservation of these relationships does not extend to Fusarium.
19 genes show conservation of syntenic relationships with humans and at least two genes appear to be duplicated in zebrafish.
Finally, we studied the evolutionary conservation of overlapping relationships between human and mouse and the possible mechanisms of transition between the overlapping and non-overlapping states.
The broad conservation of cytokine relationships across physiological scenarios points to their integrated regulation and indicates that changes in a small number of driver nodes can potentially affect the concentration of multiple downstream mediators.
The relative conservation of timing relationships within clades in the face of disparate adaptive needs is particularly striking among eutherians, which included a flying species (Rousettus), a glider (Cynocephalus), and a terrestrial species (Mus).
