Genetic specificity may be recorded in desoxyribonucleic acid (DNA) in the form of a message coded in a 4 letter alphabet. An attempt to use the mathematical ideas of information theory to study the storage, transfer, and destruction of genetical specificity is made. The process of protein synthesis in the somatic cells is regarded as a system communicating genetic specificity from DNA to protein. Shannons channel capacity theorem is applied to establish a criterion of lethality. When the channel capacity for protein synthesis is reduced below a critical value the cell dies. The theory is applied to aging and radiation damage which are 2 ways in which genetic specificity recorded in DNA is destroyed. An empirical equation shown by H. A. Blair to represent many features of the effects of radiation damage is derived from this application of information theory.