Common ancestry

Amino acid sequence analysis reveals that proteins with related functions often show a high degree of sequence similarity. Such findings suggest a common ancestry for these proteins. 

Apparently Different Proteins May Share a Common Ancestry... 

LaCount MW, E Zhang, YP Chen, K Han, MM Whitton, DE Lincoln, SA Woodin, L Lebioda (2000) The crystal structure and amino acid sequence of dehaloperoxidase from Amphitrite ornata indicate common ancestry with globins. J Biol Chem 275 18712-18716. 

Given these Lego concepts, some aspects of comparative sequence analysis are reviewed next. First it is clear that there can be at least two levels of background sequence similarity that do not reflect common ancestry. The first is the local similarity between similar types of secondary elements, and second is that between sequences of secondary elements in similar folds. Thus one should anticipate that all four-helix bundles would have greater sequence similarity than that between an all-ce and an all-/3 protein, as well as greater than that between truly random sequences. This will complicate our ability to distinguish true homology from structural similarity (Henikoff and Henikoff, 1991 Claverie, 1995),... 

Phylogenetic Common ancestry in the vertebrates Separate evolutionary lineage from the Separate evolutionary lineage from... 

A widely scattered system of phagocytic cells of common ancestry fulfilling many... 

Fig. 2. An evolution diagram illustrating a suggestion of common ancestry of some present-day organisms. The essential features of present-day photosynthesis may have originated in the prebiotic era and is preserved in its most primitive form in (at least some) present-day phototrophs. The heterotrophs may have developed parallel with the aerobic nonphotosynthetic bacteria, some l to 1.5 x 109 years after the emergence of the cyanobacteria. The eukaryotic photosynthetic organisms developed much later, perhaps some 1.5 to 0.5 x 109 years ago. The archaebacteria are primitive organisms that seem to have no evolutionary relation with the present prokaryotes.21 Little is known about their energy metabolism. Tentatively, they are considered as a very early form of cellular life.

LaCount MW, Zhang E, Chen YP, Han K, Whitton MM, Lincoln DE, Woodin SA, Lebioda L (2000) The Crystal Structure and Amino Acid Sequence of Dehaloperoxidase from Amphitrite ornata Indicate Common Ancestry with Globins. J Biol Chem 275 18712... 

Morden, C.W. and S.S. Golden (1989). psbA genes indicate common ancestry of prochlorophytes and chloroplasts. Nature, 337 382-385. 

Doolittle RF. Similar amino acid sequences Chance or common ancestry Science... 

Now that tunicates as well have a bridgehead on land, it still would not seem reasonable to draw the intermediates between a tunicate and a pig and then revert from a pig to a whale or to construct any common ancestry via this route. Nor is it plausible to say that relaxin in the pig evolved to its present state via evolutionary pressure in the pig when the gene had already been present at the tunicate stage. This was troublesome for the traditionalist. One scientific foray into the world of marine invertebrates provided a fascinating result what would a systematic survey bring out It would, I am sure, make an even more persuasive case against evolution via descent with variation. Species and proteins do not support that scheme, and therefore our funding institutions do not support that research. 

PROTEP has proved a very successful method for the detection of previously unrecognized similarities between families of protein structure with no obvious sequence homology [63-65]. In some cases these similarities may indicate a very distant common ancestry, as in the striking similarity we established between the... 

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