Most organisms contain multiple members of the Hsp70 family in virtually all cellular compartments [11].
Most organisms contain single copy Arp genes, with the exception of E. histolytica, which has two genes that encode an Arp5 [41].
Most organisms contain at least three Pex11 protein family members (see Table 2).
In contrast, most organisms contain several rpf-like genes, whose products are functionally redundant [ 3, 6- 8].
Thus, although there are exceptions (see below), centromere regions from most organisms contain repetitive sequences, suggesting that those sequences contribute to important aspects of centromere function.
Most organisms contain multiple Wnt genes which initiate distinct cellular pathways, namely the canonical Wnt/β-catenin pathway, the planar cell polarity pathway, or the Wnt/calcium pathway.
Most organisms contain two condensin complexes, condensin I and II, which share the same SMC units (MIX-1/SMC2 and SMC-4 in the worm) but differ in their regulatory subunits, termed CAPG-1, DPY-26, and DPY-28 for C.
In addition, studies are also often limited in power as there is sequencing bias within/between taxa, most organisms contain just dozens of TCS proteins, and at most taxonomic levels there is a relative shortfall in the number of available genomes, all of which can distort conclusions [ 1, 11– 13].
Another difficulty in annotating the pabAabc genes is that most organisms contain paralogs of p abAa and pabAb (trpAa and trpAb, respectively) that participate in tryptophan biosynthesis [ 52], and in some cases the PabAb (amidotransferase) subunit is shared between the pABA and tryptophan pathways [ 53].
