Helpful for topics of b.sc in molecular biology

1. 1

2. INRODUCTION
DENATURATION AND RENATURATION
COT CURVE
SIGNIFICANCE
2

3.  GENOME
It is the entire set of DNA instructions found in a
cell.
 GENOME COMPLEXITY
Relative amounts of repeated & unique DNA
sequences in an organism’s genome .
 Prokaryotic genome length is about 500kb to
about 12mb.
 Eukaryotic genome length is about 10mb in
some fungi to >100,000mb in certain plants,
frogs, salamander.
 Genome complexity is measured through
Renaturation kinetics of denatured DNA 3

4. 4

5. THE C VALUE
5

6. 6

7. 7

8. FACTORS AFFECTING
RENATURATION:
CONCENTRATION OF DNA
TIME
BUFFER FACTOR
VISCOSITY
8

9. COT CURVE
K=2nd order rate constant
C=concentration of single stranded DNA at time T.
And minus sign indicates the rate of decrease in C.
 It was discovered by ROY BRITTEN and his colleagues in 1960s
9

10. EXPRESSION:-
 Integration of some algebraic substitution shows that
 C/Co=1/1+kCot [Co= concentration Of completely denatured
DNA]
 At half renaturation
 C/Co=0.5[ at t = t1/2]
 0.5=1/1+KCot1/2
 Or, By simplifying this, 1+kCot1/2=1/0.5=2
 Or, KCot1/2=2-1=1
 Or, Cot1/2=1/K
THE PRODUCT OF Co AND T IS CALLED Cot1/2
10

11. 11

12. ANALYSIS
 During analysis singe stranded DNA find its complementary, so
that it means common sequence renature more faster than rare
Sequence
.
 Reassociation kinetics is faster in repetitive DNA
 Concentration is inversely proportional to rate constant so,
 Greater Cot1/2 …..slower the reaction
 Lesser Cot1/2…...faster reaction
12

13. APPLICATION
 COT FILTRATION(CF) SEPARATES REPETITIVE
DNA FROM GENE RICH SINGLE COPY/LOW COPY
SEQUENCES. THIS ALLOWS DNA SEQUENCING TO
CONCENTRATE ON PARTS OF GENOME THAT ARE
MORE INFOMATIVE.
REFERENCE: https://www.ebi.ac.uk/efo
13

14. SIGNIFICANCE
 Estimation of genome size.
 Estimation of the proportion of single copy and repetitive
sequences
 Interspecific comparison of cot data has provided considerable
insight into the structure and evolution of eukaryotic genome.
14

15. REFERENCE
 https://rlacollege.edu.in
 https://medium.com
 https://exama2z.com
15

16. 16