Alloenzymes are common biological enzymes that exhibit high levels of functional evolutionary conservation throughout specific phyla and kingdoms. They are used by phylogeneticists as molecular markers to gauge evolutionary histories and relationships between different species. This can be done because allozymes do not have the same structure. They can be separated by capillary electrophoresis. However, some species are monomorphic for many of their allozymes which would make it difficult for phylogeneticists to assess the evolutionary histories of these species.Parker, Patricia G. et al. (March 1998). "What Molecules Can Tell Us About Populations: Choosing and Using a Molecular Marker". Ecology 79 (2): 361–382. In these instances, phylogeneticists would have to use another method to determine the evolutionary history of a species.
