NEETZoologyMolecular Basis of Inheritance
What is a cistron in genetics?
Options
- AA segment of DNA coding for a polypeptide
- BA unit of inheritance
- CA segment of DNA that codes for a mRNA molecule
- DA DNA sequence coding for tRNA or rRNA
Correct answer
A. A segment of DNA coding for a polypeptide
Step-by-step solution
Though there is no ambiguity that the genes are located on the DNA, it is difficult to literally define a gene in terms of DNA sequence. The DNA sequence coding for tRNA or rRNA molecules also defines a gene. However by defining a cistron as a segment of DNA coding for a polypeptide, the structural gene in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mostly in bacteria or prokaryotes). In eukaryotes, the monocistronic structural genes have interrupted coding sequences