In the field of classification, it was hoped that an objective method could be developed that would establish sequential and connecting links which eluded evolutionary biologists studying life on an entire organism level. Not so. If evolution has occurred, one would expect proteins to form sequential series along evolutionary paths. This is not the case - proteins exhibit an "equidistant" pattern.
As an example, consider Cytochrome C, a protein with about 100 amino acids, which is found throughout nature and is connected with cellular energy. The sequences of amino acids found in the proteins of different organisms are compared and stated as a percentage of difference. If we look at bacterial cytochrome we see that it has the same difference between horses, tuna, yeast, etc. Instead of an orderly sequence (note: sequence here refers to a series of organisms), we see a trend of equidistance. If evolution occurred we would expect a gradual change from "lower" to "higher" organisms. This is not the case, for in this example (as well as others) the bacteria are as close to horses as yeasts!
As another example we see this when we compare the lamprey (eel-like jawless vertebrates) with a carp, frog, chicken, human, etc. Again there is a pattern of equidistance and the absence of a sequence as evolutionary theory would expect. The hypothetical fish to amphibian to reptile to mammal transition is absent. The lamprey are not primitive compared to other invertebrates nor intermediate between them.
These same trends hold true for minor biologic subdivisions as well, and when DNA or RNA are used for comparisons (Denton 1985, 287).
References: Denton 1985, 274-307 Frair 1983, 49-53