Genetic Information and Transmission

A gene is an inheritable fnnction nsed to represent a nnit of genetic information suffleient to determine an observable trait (Lewin, 1987 Omoto and Lurquin, 2004). In molecular terms, a gene is defined as the DNA sequence necessary to produce a single polypeptide or RNA molecule, while a cistron is the smallest genetic unit that encodes one polypeptide chain. 

It is well documented that DNA is the hereditary material (carrier of genetic information), except for some viral RNA. Some of pertinent observations include  

DNA is sited exclusively on the chromosome, hi prokaryotes, most of the cellular DNA is in the form of a single circular molecule on a single chromosome. However, several species of prokarytes have extrachromosomal small circular DNA molecules (l-30kbp) known as plasmids, which can reproduce independently. Eukaryotic chromosomes are highly structured complexes of DNA and proteins (histones). 

The DNA content of a cell is an absolute constant for each species consonant, with the role of DNA as the carrier of genetic information 

Mutation of genes can be produced by UV light. The action spectrum producing mutations closely corresponds to that of DNA. 

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