Recombinant DNA Recombinant DNA is foreign DNA combined
Recombinant DNA • Recombinant DNA is foreign DNA combined with a plasmid • This is how we make genetically modified organisms/Transgeneic organisms
What is a GMO? • An organism that has recombinant DNA • EX: Making rice with vitamin A so people don’t go blind • EX: Making tomatoes have an antifreeze gene so they can be harvested throughout the winter
GMO’s are referred to as genetically engineered
Steps to Recombinant DNA • 1) Isolate and cleave (cut) the foreign DNA fragment • 2) Attach DNA fragment to a “vehicle” called a Vector (the vector is a plasmid) • 3) Transfer the vector into a host to make copies
Step 1: isolate the foreign DNA
1. Isolate DNA • Cut (cleave) small pieces of DNA using a Restriction Enzyme • Restriction enzymes are bacterial enzymes that cut DNA in a SPECIFIC nucleotide sequence, called a Recognition Site • There are 100’s of Restriction Enzyme
Restriction enzyme Cut the DNA At a recognition site
Sticky Ends • Where Restriction Enzymes cut the DNA is called Sticky Ends • Sticky Ends WANT to join with DNA again, because part of it has become single stranded
Sticky ends
Vocab Checker • 1. Another word for cut is… • 2. Recognition site is a …. • • 3. The restriction enzymes job is to 4. Sticky ends are… • • 1. Cleave 2. Specific nucleotide sequence where the restriction enzyme cuts the DNA • • 3. Cleave the DNA at a specific nucleotide sequence 4. Where the DNA has been cut and it wants to rejoin
2. Attach to a Vector • The DNA fragments that have been cut, need to be inserted into a Vector (vehicle) • Vector- a way that DNA from another species can be carried into the host cell • Vectors can be biological or mechanical
Vector Examples • Biological Vectors: Viruses and Plasmids • Plasmids are small rings of DNA found in a bacterial cell • Mechanical Vectors: Micropipette or tiny metal bullet
Micropipete
Plasmid: a small ring of DNA
Connecting a plasmid with foreign DNA
This is recombinant DNA
Step 3: Transfer into a host • The recombined DNA is transferred into a bacterial cell (Bacteria = HOST) • The bacterial cell replicates up to 500 times per cell making copies of the recombinant DNA
• Each copy that the bacterial cell makes of the recombinant DNA is called a Gene Clone • Rejoining the DNA Fragments (Firefly’s glow code + the Plasmid’s DNA) is called Gene Splicing
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