THE ELECTROPHORETIC PATTERNS OF AVIAN EGG‐WHITE PROTEINS AS TAXONOMIC CHARACTERS*
Authors: SIBLEY CHARLES G. 
Published: April 2008

SUMMARYThe electrophcrctic profiles of the egg‐white proteins of 359 species of non‐passerines and at least 300 species of passerines have been studied. This paper is concerned primarily with the non‐passerines.Protein structure is genetically determined and tends to be phylogenetically more conservative than most other characters used in taxonomy. The electrophoretic profiles provide an index to some aspects of protein structure and hence to phylogenetic relationships. The present technique is described and his been found to be most informative at the generic, familial and ordinal levels. Individual variation, variation among morphological “breeds” of Domestic Fowl, and variation within species, genera, families and orders have been taken into account in the comparisons.The principal conclusions are as follows:1. The Struthioniformes and Casuariiformes arc probably related but the relationships of these to the Rheiformes are uncertain.2. The Tinamiformes do not seem to be related to the Rheiformes or to the Galliformes.3. The Pelecaniformes may be polyphyletic but this is uncertain.4. The three available species ofSulahave remarkably different egg‐white profiles. The significance of these differences is not known.5.AnhingaandPhalacrocoraxare closely related and may be included in the same subfamily.6. The Flamingos are related to the Ciconiiformes, not to the Anseriformes.7. The Gaviiformes seem to be more closely related to the Charadriiformes than to any other group.8. The Aramiclae are closer to the Rallidae than to the Gruidae.9. The Gruiformes are probably polyphyletic. There is no evidence thatEurypygaorPsophiaare closely related to the Gruidae, the Rallidae or each other.10. The Gallrormes (Opisthocomusnot studied) are a very close‐knit monophyletic group. The order is divided into three families, Megapodiidac, Phasianidae, Opisthocomidae. As subfamilies of tht Phasianidae: Phasianinae, Meleagridinae, Numidinae, Tetraoninae, Cracinae.11. The Anat dae are also monophyletic and closely related.Anseranasseems sufficiently distinctive to be placed in a monotypic tribe or possibly given subfamily status.12. The Falconiformes‐ may be polyphyletic, the Falconidae possibly being unrelated to the other diurnal birds of prey. The Cathartidae are related to the Accipitridae.13. The Strigiformes and Caprimulgiformes are related.14. Turacos (Musophagidae) are cuculiform, apparently related to the Cuculidae throughCentropus.15.Merops, Momotusand the Alcedinidae are related to one another but seem unrelated toEurystomus(Coraciidae). The Coraciiformes are therefore probably polyphyletic.16. The genusColumbais probably polyphyletic, the Old World species being distinct from the New World species.17. The Coliilormes and Trogoniformes are each distinctive and have no close relatives. Both may be related to the Passeriformes.18. The swifts and hummingbirds are related to one another and possibly to the Passeriformes.19. A request for help in obtaining additional material is made and instructions for collection and shipment art given.