This is a large question that has been very controversial, but as more and more animals are studied using an increasing number of different molecules, confidence in molecular taxonomy is growing fast also. An indication of the advantages and disadvantages of using molecules may still be useful. Advantages 1. Hie equivalence of data, since the
Gene products The differences between proteins can be revealed and estimated using gel electrophoresis, a technique invented before the genetic material itself became accessible for direct study. Techniques applied to DNA directly are now more commonly used. DNA hybridisation The paired strands of DNA dissociate when heated because the bonds between corresponding nucleotides are broken.
Early work used the proteins which are produced by gene action, but recent work has concentrated on DNA, the genes themselves. Ribosomal DNA (rDNA) The genes coding for the RNA of ribosomes (rRNA), most often the small subunit 18SrRNA, are used (the gene is called 18SrDNA). This gene is very highly conserved, i.e. has changed