Intraordinal relationships of the Pelecaniformes and Cuculiformes: electrophoresis of feather keratins

Electrophoresis of soluble feather keratins was performed in Gradipore gels under two pH conditions. The taxa of two diverse orders, the Pelecaniformes and Cuculiformes, were compared. Dendograms based on identity indices and genetic distances were constructed by the Fitch-Margoliash and unweighed pair-group algorithms (UPGMA). Differences within taxa were influenced by both pH conditions and the algorithm used for analysis.
Values of identity indices at each pH were compared within and between taxa. Dendograms for the Pelecaniform consistently group species within genera and placed families within the traditional arrangements. One notable exception was Nannopterum. The Cuculiformes, with many monotypic genera, were more resistant to constant clustering.
The problems of relating genetic distance to phylogenies are discussed. The relationship of systematic, ecological and molecular diversity is still unresolved. Genetic distance of feather keratins consistently correlated with other estimates of divergence times. The values indicate the systematic equivalence of taxa within orders.