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Slide 4 
CELL DNA 
It is quite clear that one can take a molecule which has been cut by 
that enzyme which has the cohesive ends and take a completely different DNA 
from a completely different source which has been cut by the same enzyme. 
Because this enzyme leaves such cohesive ends on any molecule it cuts, 
these two molecules can be readily joined to each other through the inter- 
action of these cohesive or sticky ends. One is therefore able to produce 
hybrid or recombinant DNA molecules which contain part of one structure 
and part of another structure, joined together by these chemical bonds. 
Now, the endonuclease, or the enzyme which was discovered that car- 
ried out this type of cleavage, making it possible to join DNA molecules, 
was only the first of a family of enzymes capable of carrying out such re- 
actions. Now we know that there are many others that can do the same 
thing, and there is no doubt that the list continues to grow as the months 
go by. 
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