Q. Why is the concept of a single gene as ultimateunit of inheritance inadequate to provide a unitary explanation for protein synthesis, recombination and mutation?

Answer:

The main function of gene is to code for a protein product. Sufficient DNA should be present to account for each of the amino acids making up primary structure of the protein. It is this length of DNA which is designated the cistron. This is the basic unit of function of the gene; however, there are units of function below this primary level. A mutation involves a change in the original message contained within cistron. Such a change may result in the manufacture of no protein Oran altered protein. Since, in some cases, change in even a single base may produce a mutation, only tiny lengths of DNA may represent a unit for mutation-the muton. Cistron may hence comprise hundreds of mutons. Minimum length of DNA participating in exchanges of genetic information isn't clearly apparent. Exchanges of relatively few bases between chromosomes would probably not result in the mutualtransfer of intact message material. Recon, unit involved in recombination, may be only slightly shorter than the full cistron.