Cot value is the product of Co ( The initial concentration of DNA) and the is the duration of Renaturation in Second.
If the percent of Renaturation plotted against log cot then it is known as cot curve. It is observed that part of the DNA is renatured quite rapidly while the rest is very slow to renature. This indicates that some sequences have higher concentration then the other that part of the genome consists of repeatative sequence. Thus repeatative DNA renature at low cot values. While complex and unique DNA sequence will renatured high cot values.
The first Renaturation of the repeated DNA is due to the availability of numerous complimentary sequence moreover, repeatative DNA sequence renature lower Cot values then single copy sequence.
Significance of cot curve:-
- Estimation of genomic size.
- Estimation of propertion of repeatative DNA sequence.
- Estimation of kinetic complexicity.
- Inter specific comparison of cot values can provide structure and evolution of Eukaryotic genome.