* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download biotechnology: tools and applications
Gene nomenclature wikipedia , lookup
Gene desert wikipedia , lookup
Epigenetics in stem-cell differentiation wikipedia , lookup
Transposable element wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
United Kingdom National DNA Database wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genealogical DNA test wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Human genome wikipedia , lookup
Oncogenomics wikipedia , lookup
Gel electrophoresis of nucleic acids wikipedia , lookup
Gene expression profiling wikipedia , lookup
DNA damage theory of aging wikipedia , lookup
Zinc finger nuclease wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Nucleic acid double helix wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Cancer epigenetics wikipedia , lookup
Genome evolution wikipedia , lookup
Genome (book) wikipedia , lookup
Primary transcript wikipedia , lookup
DNA supercoil wikipedia , lookup
Epigenomics wikipedia , lookup
Non-coding DNA wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Point mutation wikipedia , lookup
DNA vaccination wikipedia , lookup
Genetic engineering wikipedia , lookup
Gene therapy wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Extrachromosomal DNA wikipedia , lookup
Molecular cloning wikipedia , lookup
No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup
Genomic library wikipedia , lookup
Genome editing wikipedia , lookup
Microevolution wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Helitron (biology) wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Designer baby wikipedia , lookup
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings p.174 Biotechnology - use of living organisms to create products or help processes Ex. HGH, insulin Recombinant DNA - segment of DNA containing sequences from different organisms How is DNA manipulated? Restriction enzymes cut DNA at specific sites and create sticky ends G T G G T T A A C A C C A A T T A T T A C C T C C A G A G G A G G T C T G A T C G C T C T G T T C A G A A A C A C T G G C A A A G G T C T T A T GA GA T TC C C G G G T T C T T T C G A T C C A G AA C G G A A A T TC T C C TAG AG C A C G A G A C A A G C TA A G G T C T T G G C T T TA G Complementary ends will fuse to produce a long strand of DNA • The DNA is then integrated into the recipient cell’s chromosome Donated DNA Degraded DNA Crossovers Recipient cell’s chromosome Figure 12.1D Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Recombinant chromosome Plasmids are extra rings of DNA that replicate in bacteria. DNA can be inserted into plasmids. bacterium bacterial chromosome plasmid Cloning Vectors Bacterium Human cell Plasmid DNA Human protein Bacterial chromosome 1. Use restriction enzymes. 2. Insert gene into plasmid. recombinant DNA transformation 3. Transfer the plasmid back into bacterial cell. replication 4. Let bacterial cells replicate. bacterial clones Recombinant DNA products • “seed” protein for artificial snow • Insulin for diabetes treatment • Enzymes that clean up toxic waste spills • Growth Hormones (Human, Bovine) • TPA: Tissue Plasminogen Activator for treatment of heart attacks Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • The polymerase chain reaction (PCR) can quickly clone a small sample of DNA in a test tube Initial DNA segment • Selection of specific sequence 1 2 4 Number of DNA molecules Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 8 Figure 12.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gel electrophoresis sorts DNA molecules by size • Restriction fragments of DNA are compared by size Mixture of DNA molecules of different sizes Longer molecules Power source Gel Shorter molecules Glass plates Completed gel Figure 12.10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings DNA forensics Egg microinjection to produce transgenic animal Credit: © Science VU/Visuals Unlimited Egg manipulation via microinjection. Grow bigger fish faster. Salmon with gene from another fish species • Uses of transformed animals: • Produce medicines more easily Ex. sheep and gene to treat cystic fibrosis Goats and AT3 gene to prevent blood clots Figure 12.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fig. 11-14, p.173 Genetic engineering of plants Methods to insert DNA: 1. Ballistics 2. Protoplasts 3. Agrobacterium as vector - Ti plasmid Credit: © Brad Mogen An extremely large Agrobacterium tumefaciens tumor (crown gall disease) and secondary tumors on Kalanchoe stem. a A bacterial cell contains a Ti plasmid (purple) that has a foreign gene (blue). b The bacterium infects a plant and transfers the Ti plasmid into it. The plasmid DNA becomes integrated into one of the plant’s chromosomes. c The plant cell divides. Its descendant cells form an embryo, which may develop into a mature plant that can express the foreign gene. A young plant expressing a fluorescent gene product Fig. 11-12, p.171 Genetically modified crops • Golden rice with Vitamin A • Cotton resistant to boll weevil • Soybeans resistant to herbicide (Roundup) • Corn resistant to European corn borer • Rapeseed with healthier vegetable oil Benefits and risks Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How Dolly was cloned DNA udder cells white sheep embryo surrogate mother egg cell black sheep Dolly Cloning of human cells • Regenerative medicine – Bone, pancreas cells, skin Stem cells - the $6 billion promise? Gene therapy may someday help treat a variety of diseases • treat disease by altering an afflicted individual’s genes Cloned gene (normal allele) 1 Insert normal gene into virus Viral nucleic acid – Ex vivo Retrovirus – In vivo 2 Infect bone marrow cell with virus – Stem cells 3 Viral DNA inserts into chromosome Bone marrow cell from patient Bone marrow 4 Inject cells Figure 12.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings into patient Human Genome Project • 3.2 billion bases in 22 autosomes + X, Y • Draft sequence completed in 2003 • Available at www.ornl.gov/sci/techresources/Human_Genome/ home.shtml • www.ucsc.genome.edu What does the human genome sequence tell us? • 20 K to 25 K genes • 99.9% alike, across all races • 97% of DNA is not transcribed - Spacers between genes - Structural (centromeres, telomeres) - Regulatory (enhancers, promoters) - Leftovers of evolution? How are specific genes identified? 1. Isolate it from a genomic library by homology with a gene from another organism. 2. Find mRNA for the gene, make cDNA from it. 3. Make DNA sequence based on protein sequence. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 1. Nucleic acid probes identify clones carrying specific genes • A nucleic acid probe can tag a desired gene in a library Radioactive probe (DNA) Mix with singlestranded DNA from various bacterial (or phage) clones Single-stranded DNA Base pairing indicates the gene of interest Figure 12.8A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings cDNA mRNA • Complementary DNA mRNA • Using reverse cDNA transcriptase • Assembles DNA on mRNA template reverse transcriptase DNA polymerase DNA DNA Fig. 11-4, p.164 DNA microarrays test for the expression of many genes at once • A labeled probe can reveal patterns of gene expression in different kinds of cells cDNA DNA of gene DNA microarray, actual size (6,400 genes) Figure 12.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gene Therapy • What is it? • How is it done? • Does it work? Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gene therapy • Goal - Treat diseases caused by mutated genes • Method - Add a normal gene or block an abnormal gene in enough cells to restore normal function • Target - somatic cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Which disorders are candidates for gene therapy treatment? • Disorders due to mutations in one or more genes • The responsible gene is known • The affected tissues are known and accessible Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Knockout gene therapy • Goal: turn off a gene that is causing a disorder • Strategies: – Antisense – Triple helix oligos – Spliceosome – Ribozyme Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How is gene therapy done? 1. Identify the gene(s) responsible for the disorder 2. Make copies of the normal gene 3. Insert the copies into vectors (i.e., viruses) 4. Infect the affected cells with the vectors 5. Activate the gene – Transcription and translation take place Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Critical factors in choosing a vector Gene size – Limited room in vector genome • Target tissue – What cells can the vector infect? • Integration into the genome – Without integration, only short-term effect – Random integration may disrupt other genes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Photo courtesy of Van de Silva Gene Therapy Successes Ashanti de Silva successfully treated for ADA deficiency - 1990 Ryes Evans successfully treated for SCID - 2001 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gene Therapy Problems Jesse Gelsinger died of complications due to an immune system response while participating in a clinical trial Three children treated for SCID developed leukemia due to disruption of a gene that regulates cell division Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ethical and Social Issues • Patient safety while participating in clinical trials • Which applications are therapies and which are enhancements? – “Designer” babies • Access to gene therapies Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings