DNA Technology
Genetic Engineering • Using technology to manipulate the DNA of one organism by inserting DNA of another organism • Used for studying a particular gene, disease, or trait
Recombinant DNA • Combining fragments of DNA from one source with fragments of DNA from another source • Usually involve the use of bacteria cells as the host • Plasmids – small, circular pieces of DNA in bacteria
Cutting DNA • Restriction enzymescut DNA at specific sequences • Useful to divide DNA into manageable fragments
Restriction Enzymes • The cut can be made straight across a base-pair sequence resulting - "Blunt End“ • The cut can be made in an offset manner leaving exposed nucleotide sequences. These exposed sequences are called "Sticky Ends" Blunt End Sticky end
Recombinant DNA Process • Cut plasmid and DNA fragment from organism of choice with the same restriction enzyme • Join plasmid with DNA fragment using the enzyme DNA ligase (recombination) • Insert transformed plasmid back into bacteria cell
Recombinant DNA Process • Bacteria molecules containing recombinant DNA grow making many copies of identical bacteria (cloning) • Isolate the gene copied in the bacteria
Electrophoresis • DNA can be separated based on size and charge • The phosphate groups are negatively charged • DNA is placed in a gel and electricity is run through
Electrophoresis • Negative DNA moves toward the positive end • Smaller fragments move farther and faster
Electrophoresis
DNA Fingerprinting *Structural genes are often separated by large regions of repeating base pairs (junk DNA) *The number of these repeats is unique to an individual. *When DNA from a person is cut with a restriction enzyme, the length of the fragments will be unique to an individual.
DNA Fingerprinting Contd… *This will produce a unique banding pattern when run on gel electrophoresis. *This test is highly accurate, and the probability of another individual possessing an identical banding pattern is estimated as around 1:14,000,000,000.
DNA Fingerprinting
Copying DNA • Polymerase Chain Reaction • Also called PCR • A method of making many copies of a piece of DNA
PCR Large amounts of DNA can be made from a small starting sample
Cloning • Clone- a member of a group of genetically identical cells • May be produced by asexual reproduction (mitosis)
Cloning organisms • A body cell from one organism and an egg cell from another are fused • The resulting cell divides like a normal embryo
Cloning “Dolly”
Stem Cells • A human embryo up to 14 days is a ball of undifferentiated cells called stem cells • They have the potential to develop into various types of cells
Stem Cells • As an adult, you have some stem cells (bone marrow), but they can only develop into certain types of tissue • Embryonic stem cells have the potential to help people with disabling diseases that affect tissues
Human Genome Project
Human Genome Project • Started in 1990 • Research effort to sequence all of our DNA (46 chromosomes) • Over 3.3 billion nucleotides • Mapping every gene location (loci) • Conducted by scientists around the world
HGP Insights • Only 2% of human genome codes for proteins (exons) • Other 98% (introns) are non-coding • Only about 20,000 to 25,000 genes (expected 100,000) • Proteome – organism’s complete set of proteins • About 8 million single nucleotide polymorphisms (SNP) – places where humans differ by a single nucleotide • About ½ of genome comes from transposons (pieces of DNA that move to different locations on chromosomes)
Benefits of Human Genome Project • Improvements in medical prevention of disease, gene therapies, diagnosis techniques … • Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries. • Improved bioinformatics – using computers to help in DNA sequencing …
Benefits of Genetic Engineering
Biotechnology - • The use of gene science to create new products from plants and animals
BiotechnologyProvides: • Improved food products • Medical advances • An enhanced environment
Herbicide Resistant Crops • Soybeans: Roundup Ready • Corn: Roundup Ready, Liberty Link • Cotton: BXN, Roundup Ready • Canola: Liberty Link, Roundup Ready + CP4 EPSPS = Roundup gene Ready
Biotechnology Breakthroughs • Insulin (1982) • First commercial biotech product • Reliable, inexpensive source of insulin • Rice • Enriched with beta-carotene and iron • Bananas • Containing edible hepatitis vaccine
Biotechnology Breakthroughs • Potatoes with higher solid content • Garlic that lowers cholesterol • Fruits and vegetables that reduce risks of cancer and heart disease
Environmental Benefits • Reduced pesticide use • Lower energy requirements • Cleaner water • Less soil erosion
