Distinction within prokaryotes, formingthe primary taxonomic division within them, which is supported by both molecular sequence data and morphological features, is of the monoderm prokaryotes (Monodermata, i.e., those bounded by a single cell membrane) and the diderm prokaryotes (Didermata, i.e., those bounded by inner and outer cell membranes defining a periplasmic compartment). In that sense, b
E signature sequences in different proteins support the division of Archaebacteria into two distinct groups (Euryarchaeota and Crenarchaeota) and of gram-positive bacteria into at least two groups, corresponding to the low-G C and high-G C species, of which the high-G C group is specifically related to the diderm prokaryotes. The DeinococcusThermus group of species appears to be intermediate in th
Sp70 (Fig. 26) and Hsp90 (Fig. 31) also contain several unique sequence signatures not found in any prokaryotic homologs. These signature provides evidence that all of the eukaryotes are derived from a single ancestor and that the postulated fusion event was unique.VOL. 62,PHYLOGENY OF PROKARYOTES AND EUKARYOTEScluding amitochondriate and aplastidic cells, received major gene contributions to the
Sp70 (Fig. 26) and Hsp90 (Fig. 31) also contain several unique sequence signatures not found in any prokaryotic homologs. These signature provides evidence that all of the eukaryotes are derived from a single ancestor and that the postulated fusion event was unique.VOL. 62,PHYLOGENY OF PROKARYOTES AND EUKARYOTEScluding amitochondriate and aplastidic cells, received major gene contributions to the
Oteobacteria). The evolutionary history deduced here based on signature sequences in some of the most highly conserved protein sequences in the biota is in contrast to the rather confusing picture that seems to be emerging from other analyses of the completed bacterial genomes (21, 50, 68, 130, 143, 144, 182, 191, 255). However, as has been pointed out (50, 143, 144, 182), of the large number of s
Oteobacteria). The evolutionary history deduced here based on signature sequences in some of the most highly conserved protein sequences in the biota is in contrast to the rather confusing picture that seems to be emerging from other analyses of the completed bacterial genomes (21, 50, 68, 130, 143, 144, 182, 191, 255). However, as has been pointed out (50, 143, 144, 182), of the large number of s
Ents was preceded or accompanied by duplication of the genes for the chaperone proteins (Hsp70, Hsp90, DnaJ, etc.), which are necessary for protein transport and communication within the compartments. The transfer of the genome from the gram-negative eubacterium to the newly formed nucleus and an assortment and integration of genes from the two partners led to the formation of the ancestral eukary
Karyotic cell nucleus and endomembrane system as per the chimeric model. The key event in the origin of the eukaryotic cell is postulated to be a symbiotic association between a gram-negative eubacterium (from the proteobacteria-1 group) and likely an "eocyte" archaebacterium. This association led to the loss of the outer membrane from the gram-negative bacterium (not shown). As the membrane of th