1. Rodney F. Boyer, Modern Experimental Biochemistry, Addison-Wesley Publishing Company, Inc., 2000. 2. Keith Wilson and John M. Walker, Principles and techniques of practical biochemistry, Fourth edition, Cambridge University Press, 1994
Ribosomal RNAs as Evolutionary Chronometers Reasons: Ancient molecules Functionally constant Universally distributed Moderately well conserved in sequence across broad phylogenetic distances