Unit 4: Biotechnology

Human Genome Project

mapping the entire humane genome; began planning in 1987; complete genome published in 2003; 20500 total genes in human DNA; may help determine causes and develop treatments for many diseases

DNA Manipulation

DNA is extracted, cut, and separated; used to produce synthetic insulin; might involve stem cells in forming new tissue

Gene Therapy

replacing defective genes w/normal ones to treat genetic diesases (ex. sickle cell, diabetes, colorblindness, cystic fibrosis); can correct a protein/enzyme deficiency; popular gene therapy uses viruses’ ability to hijack cells and create more of their genetic material; viruses are altered to be nonvirulent, then deliver healthy gene copies into cells

Cloning

genetically identical indvidiuals processed from a single cell; Dolly the sheep was the first mammal to be clone; clones don’t look exactly like their mothers

Selective Breeding

select for the desired trait to pass on to future generations; common w/dog breeds & livestock animals

Hybridization

cross 2 dissimilar organisms to create a new individual; lion + tiger = liger; horse + donkey = mule

Transgenic Organisms

organisms that contain genes from another organism; “GMOs” like soybeans; can help grow crops in inhospitable climate conditions

Bacterial Transformation

plasmid removed from bacteria by restriction enzymes; new gene is inserted into plasmid; plasmid is replaced in bacteria

Genetic Engineering

process of modifying an organism’s genome/DNA by introducing a gene from another organism belonging to a different species; desired gene is cut out of the DNA of one organism using restriction enzymes and inserted into the DNA of a second organism; done at a very early stage of development

How is bacteria genetically modified to produce insulin?

the plasmid is removed from the bacterium and cut open using restriction enzymes; gene for insulin is cut from human chromosome using same restriction enzyme; insulin gene is inserted into the plasmid and sealed using another enzyme (ligase); plasmid is put back into the bacterial cell; bacterium and its offspring can produce insulin

What are the benefits of genetic engineering?

genetically modified food could be used to deliver vaccines more easily and at a lower cost; GM crops can be resistant to diseases & insect attachs (food supplies are more steady); can cure genetic diseases like cystic fibrosis & Huntington’s disease; GMOs can be larger & better quality (more & better food); GM crops can be herbicide resistant

What are the risks of genetic engineering?

some ppl may create designer babies by altering their future children’s genes to change their appearance (ethically wrong); GM crop genes can spread into wild plant populations causing ecological imbalances; GMOs can be unhealthy (haven’t been eating long term); unethical to interfere w/nature like this; GM food can cause allergic reactions

Selective Breeding

humans breeding plants/animals for particular genetic characteristics over many generations; involves choosing mates; done to ensure offspring have desirable traits (ex. high milk production in dairy cows)

What are the ethical issues involved w/selective breeding?

causes inbreeding due to closely related individuals being bred together (reduces gene pool, causing problems); species w/high amt of selective breeding at higher risk of genetic diseases (ex dog breeds, pugs have respiratory problems due to flat faces); may be unethical for humans to pick and choose mates of animals and manipulate gene pools for own benefit

What are some examples of selective breeding?

cattle being bred to grow quickly & produce lots of meat & milk; plants being selectively bred to produce large, unusual, & beautiful flowers; crops may be bred to be resistant to disease (ensures steady food production); domestic dogs being bred for gentle & friendly natures towards humans

Biotechnology

use of an organism to achieve a specific goal; produces many product used in daily life; ex. using yeast to bake, growing animal parts to replace human organs; 2 types: simple (ex. growing mold for penicillin) and advanced (manipulating DNA aka genetic engineering)

Vectors

viruses & bacteria have naturally occurring enzymes & proteins that can manipulate DNA; many modern biotechnologies use viruses/bacteria as vectors to modify DNA

What are examples of biotechnology?

DNA fingerprinting, genetically modified organisms, gene therapy

DNA Fingerprinting

popular in forensics to compare known DNA samples to sample in question using DNA electrophoresis

Genetically Modified Organisms

organisms that have had their DNA modified to express a desirable trait; sometimes GMOs contain DNA from 2 species (transgenic); can be achieved using bacteria and/or viruses as vectors to cut & paste DNA

Gene Therapy

replacing a defective gene w/a healthy version using viruses as vectors to deliver DNA

Gel Electrophoresis

lab technique used to distinguish DNA fragments of different lengths; DNA is separated & pushed through an electrical field through an agarose gel; electro = electricity; phoresis = to carry; DNA can be carried by electrical currents bc they are negatively charged; larger fragments do not move as far as smaller fragments, so larger are found closer to top, smaller closer to the bottom; samples are compared to a DNA marker that contains known sizes of DNA fragments in base pairs; DNA moves from negative side to positive side; DNA is stained w/a special dye that can be seen under UV light

What is gel electrophoresis used for?

Forensics: used for DNA fingerprinting; bands of DNA have patterns specific to an individual due to the size & sequence; must be 100 match; used to match suspects to a crime; Zoology: mapping endangered species, exploring pedigrees; Paternity: determins parents; 50% of DNA comes from mother, 50% from father; all bands must be accounted for; also used to analyze PCR results and isolate & analyze genes associated w/a disease

Transgenic

a transfer of a gene from one species to another

Transgenic Organisms

have had their DNA manipulated to express a foreign gene; contain DNA from two species; all are GMOs, but not all GMOs are transgenic; created w/bacteria through recombinant DNA technology; bacteria & enzymes in plasmid based transformation are used to insert genes

What are examples of transgenic organisms?

transgenic goats have been genetically modified to produce spider silk; corn & cotton contain a gene from bacteria that is resistant to insects; sugar beets & soybeans contain a gene from bacteria that is resistant to herbicides

Recombinant DNA

molecules of DNA from 2 different species that are inserted into a host organism to produce new genetic combos

DNA Recombinant Technology

aka DNA cloning; joining of DNA from two diff species; process of making many copies of DNA sequence in order to make lots of protein; copies are typically made in bacteria by introducing foreign DNA into a plasmid; ex. producing insulin

Plasmid Transformation

cutting & pasting DNA from one organism to another; requires enzymes; bacteria takes up foreign DNA during this process; used to target a gene of interest from one organism & introduce it into the genome of bacteria to create recombinant organisms; uses plasmids; bacteria can replicate quickly and create many copies of DNA and proteins

Restriction Enzymes

enzymes found in bacteria that recognize & bind to specific DNA sequences called restriction sites, and cut DNA at specific spots

DNA Ligase

enzyme that seals or pastes DNA nucleotides together

Retrovirus

popular treatment for gene therapy; has RNA genome; infects host cell, then synthesizes complementary DNA from RNA (through reverse transcription)

How do retroviruses work in gene therapy?

healthy gene is transcribed into RNA; retrovirus then makes a copy of DNA from the healthy RNA, and inserts it into host cell; host cell them starts making needed proteins

What are the two types of gene therapy?

in vivo (more common) and ex vivo

In Vivo Gene Therapy

more common; modified DNA/viruses are injected directly INTO pt’s tissues

Ex Vivo Gene Therapy

cells & tissue are taken out of pt, modified outside of body, and injected back into tissues; less successful; not all cells survive; takes lots of cells from pt, which can be harmful

CRISPR

aka Clustered Regularly Interspaced Short Palindrome Repeats; natural defense mechanism against viruses in bacterial cells; describes repeating pattern in E.coli; found between spacer DNA; follows Palindrome pattern; matches perfectly w/viral DNA (bacteriophages that invade bacteria); can cut and add DNA to cure genetic diseases (diabetes); has been modified to work w/eukaryote DNA; has 2 main components: RNA & protein

CRISPR-Cas

provides sequence-specific adaptive immunity in bacteria; snips viral DNA & integrates short virus DNA sequences in bacteria’s CRISPR locus; allows cell to recognize & clear viral infections; Cas is special protein required for this immunity