In contrast to the cilia model, which must postulate divergent origins of asymmetry in animals such as mouse, pig, chick, frog, and invertebrates, the intracellular model is compatible with an ancient, highly conserved role for the symmetry-breaking mechanism.
It should be remarked that while the divergent development of neurons and glial cells (including astrocytes) is well studied [ 38, 39], there is little known about the divergent origins of protoplasmic, CD44+ long process, and fibrous astrocytes.
However, their individual sequence identities with Pleos-DyP4 were always below 40%% (and only 176 191 residues could be aligned) suggesting a divergent evolutionary origin of the latter protein.
These observations suggest that plant-like FADS proteins have a prokaryotic origin closely related with cyanobacteria, although shaping a divergent group of sequences, as illustrated in Figure 3.
Phylogenetic analysis indicates a unique origin of a strongly divergent nucleotide stretch (purple, fig. 2 B and C ) and the insertion of a palindromic genetic element, which should be considered as a discrete event in the ancestry of the population.
To test for a shared origin of the two divergent alleles, we compared the best tree with an alternative topology in which f. poultoni and f. planemoides were constrained to monophyly.
The sequence of its homeodomain assigns ARGFX as a divergent member of the PRD class [ 6], but gives no clear solution to its mode of origin.
They come from wildly divergent origins, but eventually succumb to the same middle-class temptations (Nora leads Nick out of his San Francisco apartment into a single house with a big back yard) and acquire the same grown-up responsibilities.
