Altering DNA

POINT > Define and describe recombinant DNA POINT > Show how bacterial plasmids are used in recombinant technology POINT > Define and describe transgenic organisms POINT > Identify uses of recombinant DNA

Recombinant DNA is DNA formed by joining DNA fragments together (by utilizing “sticky ends”) This allows combinations of DNA segments from different organisms (due to universal base pairing rules)

Plasmids are small, circular DNA molecules found in bacteria (in addition to their own chromosome) In nature, plasmids usually carry genes for resistance (antibiotic, chemical) In research, plasmids are used to insert recombinant DNA into bacteria, which then amplify the gene

Plasmids contain a genetic marker, usually a gene for antibiotic resistance Only bacterial cells that have the plasmid will survive when grown in the presence of an antibiotic

WB CHECK: What is a plasmid? Where would you find a plasmid? What do plasmids do for bacteria? What do researchers use plasmids for?

A transgenic organism contains one or more genes from another species or another individual Scientists use recombinant DNA & plasmids to create transgenic organisms

Transgenic Plants Agrobacterium is a species of bacteria that inserts DNA plasmids into plant cells, resulting in tumors Scientists use Agrobacterium to get new DNA into plant cells

Transgenic plant production steps: 1. Tumor-causing gene in Agrobacterium plasmid is replaced with recombinant DNA of interest 2. Plants infected with the bacteria will contain the gene of interest in their genome 3. The new plant grows and expresses the transferred gene 4. Micropropagation allows for many identical plants to be produced quickly

WB CHECK: What is a good bacteria to use if you want to put a new gene into a plant? What is a transgenic organism?

WB CHECK: Which of these events would be first? a)Allow Agrobacterium to infect the plant cells b)Cut the plasmid and new gene with the same restriction enzyme c)Use DNA ligase to fully recombine the plasmid and the new gene d)Use micropropagation to make many identical plants Place a-d in logical order

Transgenic Animals Animals cells can be transformed by directly inserting DNA into the nucleus Enzymes responsible for DNA repair can function to insert the recombinant DNA into chromosomes

Animal cloning: a new individual is grown from a single cell of an adult organism The clone is genetically identical to the adult the cell was taken from The process is difficult and expensive, and cloned animals tend to have shorter lifespans (not understood)

Cloning:

WB CHECK: Which of these events would be first? a)Put the nucleus of an adult donor cell into an egg cell b)Implant the egg cell into a surrogate mother c)Allow recombined egg cell and nucleus to divide d)Remove the nucleus from an adult egg cell Place a-d in logical order

Genetically Modified Crops & Animals (GMOs) Preventing & Treating Disease (Gene Therapy) Medical Research Genetic Testing (for disease, etc) Personal Identification (Forensics, Relationships)

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