Molecular Techniques
The first use of genetic data to disecern information about phylogenetic trees, although indirectly, was in an experiment at the turn of the twentieth century by the biologist George Henry Faulkner Nuttall. In his study of 1904, Blood Immunity and Blood Relationship, he was comparing immunological characteristics of certain blood proteins of primates, including humans. Although long before the molecular basis of inheritance had been determined, Nuttall's experiment revealed that humans were more closely related to African apes than Asian apes based on proteins of the blood.
It was not until the 1960's however, with the understanding of the role of DNA in heredity and the production of proteins, that it was assumed that a molecular approach to phylogeny would be significantly more successful than morphology. Among the first techniques to be developed were immunodiffusion and DNA-DNA hybridisation. Both techniques are 'distance measures', and measure the degree of difference between two molecules, whether it be two proteins or two strands of DNA.
In the last two decades the more recently developed techniques of protein sequencing and DNA sequencing have revolutionised molecular systematics, and the development of more effective and efficient computational methods has meant that both techniques can be used more extensively and much more rapidly.
For a description of the development and implementation of the molecular methods mentioned above click on the following links: