Chargaff’s First Parity Rule

Abstract

Consider a creature, whose attributes you are probably familiar with, perhaps pausing in a posture similar to that which you are now adopting: The cat sat on the mat. The cat sat on the mat. You might guess that, since the information is repeated and rhythms, it forms part of some artistic endeavour that we might refer to as poetry. Alternatively, the author may have had little faith in the typesetters and, to make assurance doubly sure, sent the message twice. It is with the latter explanation that we are most concerned at this point.

“The formation of different languages and of distinct [biological] species, and the proofs that both have been developed through a gradual process, are curiously the same. ... Languages, like organic beings, can be classed in groups under groups. A language, like a species, when once extinct never ... reappears. The same language never has two birthplaces... The survival or preservation of certain favoured words in the struggle for existence is natural selection.” Charles Darwin (1871)[1]