Genetic Technologies

Transcription

1 Genetic Technologies Distinguish the terms biotechnology, recombinant DNA technology, transgenic organisms, genetic engineering Understand the two basic techniques to obtain selective fragments of DNA from any organism in large quantities: Polymerase Chain Reaction (PCR) & recombinant DNA Technology Explain the tools of recombinant DNA Technology: genomic DNA, plasmids, DNA modification enzymes (restriction enzymes and ligase) Explain the term transgenic organisms, animals and plants, and their utility Explain DNA profiling as it is used in forensics

2 Definitions Technology: the practical application of science to commerce or industry Biotechnology: the science of using living cells, and components of living cells, to produce goods and services.

3 What is Biotechnology? The use or alteration of cells or biological molecules for specific applications to solve problems or make useful products

4 Definitions Engineering: exploiting basic mechanical principles to develop useful tools and objects Genetic engineering: Developing useful tools using genetic material (DNA)

5 Recombinant DNA an engineered molecules of DNA from more than one type of organism A transgenic organism has DNA from different species Both are possible because of the universality of the genetic code Both are considered intellectual property

6 Intellectual Property- the product of a person s or company s originality & creativity Patents- Copyrights for an invention that is Novel Non-obvious Useful Reduced to Practice (You should have done it) Benefit individual inventors & companies (exclusive rights to innovative products) - Opportunity to profit from invention - Distribute technological information to others - May be the entire asset of a biotech company - Documentation

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8 The Patent Thicket Term used to describe the need to license patents for every SNP or snippet of DNA Suggested ways around this: - Allow DNA to be patented only for use in diagnostic tests - Exempt individuals from litigation if they use patented DNA sequences A broader action is to ban patenting any DNA or its encoded proteins

9 Genetics Technologies Applications based on basic understanding of molecular genetics - DNA replication - Transcription - Translation - Control systems regulating all these processes

10 Amplifying DNA Polymerase chain reaction (PCR) - Works on DNA molecules outside of cells - Replicates sequence millions of times Recombinant DNA technology - Amplifies DNA within cells often using sequences from other organisms

11 PCR Consists of a repetition of three basic steps: 1. Denaturation: Heat is used to separate the two strands of target DNA 2. Annealing: Two short DNA primers bind to the DNA at a lower temperature 3. Extension: The enzyme Taq1 DNA polymerase adds bases to the primers Copies of DNA accumulate exponentially All this is done in a thermal cycler nimations.html#

12 Table 19.1

13 Recombinant DNA Technology Recombinant DNA technology is also known as gene cloning Started in 1975, safety than expected Tools DNA modifying enzymes - Restriction enzymes - Ligase Cloning vectors, plamsids

14 Restriction Enzymes Molecular scissors that cut donor and recipient DNA at the same sequence The cutting action of many of these enzymes generate single-stranded extensions called sticky ends or cohesive ends mations.html#

15 Plasmids Extra-chromosomal small circular pieces of DNA- plasmids Found in most bacteria, fungi, and plants but not in animal cells Multiply independently of bacterial chromosome

16 Creating Recombinant DNA Molecules Cut DNA from donor and plasmid vector with the same restriction enzyme Mix to generate recombinant DNA molecule When such a modified plasmid is introduced into a bacterium, it is mass produced as the bacterium divides pter16/animations.html#

17 Biotechnology to produce useful products

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19 Table 19.3

20 Transgenic Animals An even more efficient way to express some recombinant genes is in a body fluid of a transgenic animal Transgenic sheep, cows, and goats have all expressed human genes in their milk, - Clotting factors - Clot busters - Collagen - Antibodies

21 DNA Profiling Developed in the 1980s by British geneticist Sir Alec Jeffreys Also called DNA fingerprinting Identifies individuals Used in forensics, agriculture, paternity testing, and historical investigations

22 DNA Gel electrophoresis ectro.htm Restriction Fragment length Polymorphisms (RFLPs) mations.html#

23 Isolation of DNA DNA Fingerprinting Cutting, sizing, and sorting DNA. Special enzymes called restriction enzymes Producing a DNA profile of fragments that appear as bands (using many alternative techniques..)

24 Practical Applications of DNA Fingerprinting Paternity and Maternity Personal Identification/ Criminal Identification and Forensics

25 Practical Applications of DNA Fingerprinting Forensic Biotechnology Whodunit? by Jenny Shaw, Vanessa Petty, Theresa Brown, and Sarah Mathiason

26 Practical Applications of DNA Fingerprinting

27 DNA can be obtained from any cell with a nucleus STRs (short tandem repeats) are used when DNA is scarce If DNA is extremely damaged, mitochondrial DNA (mtdna) is often used For forensics, the FBI developed the Combined DNA Index System (CODIS) - Uses 13 STRs DNA Sources

28 CODIS Figure The probability that any two individuals have same thirteen markers is 1 in 250 trillion

29 Population Statistics Is Used to Interpret DNA Profiles The power of DNA profiling is greatly expanded by tracking repeats in different chromosomes The number of copies of a repeat are assigned probabilities based on their observed frequency in a population The product rule is then used to calculate probability of a certain repeat combination

30 To Catch A Thief With A Sneeze Table 14.6

31 Animal Cloning Distinguish between reproductive cloning of whole organisms and therapeutic cloning Explain nuclear transplantation that was used to clone the first mammal, Dolly the sheep Explain the difference between adult and embryonic stem cells in their ability to produce different tissues. What is the difference between totipotency and pluripotency or multipotency (the last two are the same) Recognize Somatic Cell reprogramming as a novel technology to revert differentiated somatic cells into a phenotypically undifferentiated stem cells

32 Animal Cloning Reproductive Organism Therapeutic Tissues & Organs

33 Early Studies of Animal cloning Nuclear transplantation

34 In nuclear transplantation, only 2% of eggs generated using diploid nuclei of differentiated cells develop normally Different types of cell in an organism have the same DNA but they transcribe different genes Nuclei do change as cells differentiate: DNA sequences do not change Chromatin structure and methylation patterns do

35 Cloning of a Mammal In 1997 by Ian Wilmut edu/units/cloning/whatiscl oning/

36 Other mammals have been cloned The possibility of cloning humans raises unprecedented ethical issues.

37 Stem Cell Research Stem cells unspecialized cells, continually reproduce can differentiate into specialized cell types. can differentiate into multiple cell types Three types of stem cells 1. Adult stem cells 2. Cord Blood stem cells 3. Embryonic stem cells

38 Under the right conditions, cultured stem cells derived from either source can differentiate into specialized cells.

39 Adult stem cells Pluripotent: bone marrow stem cellsdifferent kinds of blood cells Embryonic stem cells Totipotent- immortal Somatic Cell reprogramming (2007) Induced Pluripotent Stem Cells (ipsc) Oct , 11:21 AM EST Induced Pluripotent Stem Cell Technology Used to Generate Hepatocytes from Skin Cells GEN News Highlights