Development of a novel classificatory method — Use of amino acid nearest neighbors as an objective key

The distribution of overlapping dipeptides found within the amino acid sequence of a protein is biassed, i.e. some dipeptides occur exclusively within angiosperms, some within vertebrates etc., while others are absent from the same organisms. Thus, utilization of the amino acid sequences of the members of a family of homologous proteins, such as cytochromes c, may lead to an objective classificatory system.