How trasnposeable elements works? How they jump from one locus to another? Here you can learn all about them. This is by Tahir 52.

1. Transposable Elements

2. Introduction
• Name khurram shahzad
• Roll no. 876
• Uni roll no. 023794
• Assignment on . Transposable Elements
• Subject . Molecular genetics
• Teacher name . Dr. Tariq

3. Definition
• Transposons is a class of genetic elements that can
jump to different locations with in a genome.

4. Jumping genes
These are also called jumping genes because these jumps
from one location to another location on chromosomes.

5. Mechanism
• Their are two mechanism by which transposons
jumps .
• 1) Replicative mechanism
• 2) Non replicative mechanism

6. Replicative mechanism
• It is also know as copy paste mechanism .
• In this mechanism one strand is copied and then
transfer to another strand .
• The reslut of this mechanism one copy appear at
new strand and one copy remains at old strand .

7. Non replicative mechanism
• It is also know as cut paste mechanism
• In this mechanism element is excised from one
strand and integrated into a new strand .
• In this mechanism element is lost from the site of
the original chromosome.
• In this mechanism two enzymes are used
• 1) endonuclease use to cut element
• 2) ligase is use to join two strands

8. Steps of replicative mechanism
• The explanation of strand transfer mechanism for
DNA transposon is following

9. Step 1
• Transposase enzyme assemble at two ends of
Transposable Elements.
• Then cleaving and joining reaction take place
• In this reaction transposon is cut from one place
and joined to another place

11. Step 2
• This step is carried by transposase protien
• Transposas protien cleave DNA at two terminals of
transposable element and creat 3' OH end .
• It also creat gap in target DNA .
• Overall four knots are created.

14. Step 3
• In this step double branch DNA molecule formed by
the strand transfer mechanism.
• 3' prime end that was created in previous step is
joined to the 5' end of host DNA.
• The bond is covalent.
• 5' end of transposon sequence remain bound with
old strand

16. Step 4
• In this step replication occurred through the
transposon and end at another end .
• Replication fork is created and facilitate a normal
replication into the target DNA.

18. Step 5
• In the last step at end of the replication ,two DNA
molecules each with the transposon are generated
at the end of the process

21. Non replicative mechanism
• Its is also known as cut paste mechanism .
• This mechanism is take place in three steps .

22. Step 1
• First the enzyme transposas make a double strand
cut in the donar DNA at the end of the transposon
and make a staggered cut in the recipient DNA .

23. Step 2
• Each end of the donor DNA is then joined to an
over hanging end of the recepient DNA.

24. Step 3
• DNA polymerase fills in the short over hanging
sequence , resulting in a short , direct repeat on
each side of the transposon insertion in the
recipient DNA.