Topic 4.4 Genetic Engineering and biotechnology

Topic 4.4 Genetic Engineering and biotechnology
Unit 4: Genetics Topic 4.4 Genetic Engineering and biotechnology

4.4: Genetic Engineering and Biotechnology
DNA gives organisms a uniqueness and allows scientists a method for exploring and manipulating it. Procedures for exploring DNA are as follows: Copying DNA in a laboratory – polymerase chain reaction Using DNA to reveal its owner’s identity – DNA profiling Mapping DNA by finding where every A, T, C, and G is – Human Genome Project Cutting and pasting genes to make new organisms – gene transfer Cloning cells and animals 1. Polymerase Chain Reaction (PCR): is a laboratory technique which takes a small quantity of DNA and copies all of the nucleic acids in it to make millions of copies of the DNA.

Purpose: amplify and copy DNA Simple solution on how to get enough DNA to be able to analyze it Used during investigations when only a small amount of DNA is found and more DNA is needed DNA is obtained from cells available at crime sciences (blood, urine, semen, and even your cheek smear!) Identify a process PCR is similar to: PCR mimics meiosis. The DNA, like chromosomes in meiosis will divide and replicate the exact copy of it repeatedly. REPLICATION! Role of high temperatures in PCR use: high temperatures help break down/degenerate the enzymes and break the hydrogen bonds in a DNA molecule. DNA polymerase is used during this process

Role of complementary base pairing: helps assure the bases combine with the right base. No substitutions or mutations. Describe chain reaction: it is give than name because the DNA is repeatedly being copied over and over. Kary Mullis – Making Copies of DNA Defined Kary Mullis – Naming the PCR Finding DNA to Copy PCR Animation

2. Gel Electrophoresis: method used to separate fragments of DNA in an effort to identify its origin. Enzymes are used to chop up the DNA into different sizes. Enzyme is called a restriction enzyme DNA placed into small wells in gel which are aligned along one end. Gel is exposed to an electrical current. Biggest fragments – move slowly because they are the least charged Smallest fragments – move quickly because they are the most charged

Components and Functions of Gel Electrophoresis (Key Players) Restriction Enzymes – cut DNA at specific base sequences Gel – acts like a “sieve” Electric current – pushes the fragments of DNA that have been cut by the restriction enzymes Small moves the farthest Fluorescent DNA markers – helps show the banding pattern of the DNA sample (makes it easier to see)

Gel Electrophoresis Animation

DNA Profiling: process of matching an unknown sample of DNA with a known sample to see if they correspond. Also called genetic/DNA fingerprinting OR DNA profiling Reasons for use: Paternity testing – baby daddy Forensics – crime scene application (blood/semen collection) Helps with studying ecosystems – social relationships among organisms, migrating patterns, nesting habits. Basis for evolution! Making a DNA profile requires 2 parts: 1. Polymerase Chain Reaction (PCR) 2. Gel Electrophoresis

DNA profiling How DNA profiles are analyzed

In each picture, circle the guilty suspect or real father! 4.4: Genetic Engineering and Biotechnology

The Human Genome Project (HGP): International cooperative venture set out to sequence the complete human genome. A genome of an organisms is a catalogue of all the bases it possesses, Human Genome Project hoped to determine the order of all the bases A,T,C, and G. Project completed in 2003 Now scientists are focusing on deciphering which sequences represent what gene and what they do The human genome can be thought of as a map to show the locus of any gene on any one of the 46 chromosomes.

The Human Genome Project (HGP): Goals Keep and store info about databases Improve tools and technology used for the data analysis Recognize all the genes in human DNA (around ) Share connected technologies to private areas of science Talk about and solve the ethical, legal, and social issues that may come up because of the project Find and classify the sequences of the base pairs that makes up human DNA

Advantages/outcomes of the HGP: 1. Easier identification of human diseases Some diseases are sex-linked (easy to tell where it is located). Difficult to identify with non-sex linkage disease With libraries doctors can find out where to look

2. Production of new medications Beneficial molecules which are produced naturally Which gene controls the synthesis of desirable molecules Copy that gene and use it as instructions to synthesize the molecule in a laboratory Distribute beneficial molecule for new medical treatment

Gene Transfer: Technique of taking a gene out of one organism (the donor organism) and placing it in another organism (host) Ex: Tomatoes made to be more resistant to cold and frost Proteins came from fish to help tomatoes because resistant; fish were resistant to icy temperatures in the Artic It is possible to put one species' genes into another's genetic makeup because DNA is universal!

Gene transfer is possible because the genetic code is universal. No matter what the species, amino acids translated to polypeptides, then proteins, stays the same. Usually, in gene transfer, only one gene at a time is transferred to another species. EX: our gene for blood-clotting has been transferred to sheep which produce this gene in their milk. Humans drink this milk who have blood clotting problems.

Gene for resistance to cold Genetically engineered tomato is more resistant to cold Arctic Fish Remember all living organisms have the same bases (A, T, G, C) which code for proteins. The codons they form always code for the same amino acids, so transferred DNA codes for the same polypeptide chain in the host organism as it did in the donor organism.

Gene for pest-killing toxin Genetically engineered corn is resistant to pests Bacteria Gene transfer is found in Bt-corn, which has been genetically engineered to produce toxins that kill the bugs that attack it. The gene comes from a soil bacterium, Bacillus thuringiensis, thus Bt, which has the ability to produce a protein that is fatal to the larvae of certain crop-eating pests.

Cutting, copying, and pasting genes: “Scissors” cut base sequences in a DNA molecule. The scissors are restriction enzymes or endonucleases. Find and recognize a specific sequence of base pairs along the DNA molecule Endonucleases cut the DNA at certain points If beginning and end are cut, gene is released For pasting genes, DNA ligase is used. Recognizes the parts of bases sequences that are supposed to be clicked together and attaches them.

Restriction Enzymes Videos/Animations

Steps to Gene Transfer: 1. Plasmid (circular DNA molecule) is removed from the host cell. 2. Plasmid is cut open using a restriction enzyme called endonuclease. 3. The gene to be copied is placed inside the open plasmid. This is called gene splicing. 4. Gene is pasted into the plasmid using DNA ligase. 5. Plasmid is now a recombinant plasmid. 6. Gene then is placed inside a host to grow or proliferate. (Cloning)

Genetically Modified Organisms (GMOs) Transgenic Organism: A GMO is one that has had an artificial genetic change using the techniques of genetic engineering such as gene transfer or recombinant DNA. End result – does not show undesirable trait or is genetically modified Role of restriction enzymes in gene transfer: cut the gene that is desired from the genome and the plasmids too FIRST EXAMPLE of GMO: Insect Resistant Corn (Transgenic Plant) Maize often damaged by insect borers. A gene from a bacterium (Bacillus thuringiensis, or Bt) can be transferred to maize. Then this gene transfer allows corn to produce the Bt toxin that kills the insect's larvae. Advantage – farmers will not have to use poisonous insectides on the corn while keeping the pest away from the corn at the same time.

SECOND EXAMPLE of GMO: Flavr Savr Tomato – first commercial example Genetically modified to delay ripening and rotting process to stay fresh longer Advantage – longer shelf life Project later abandoned due to cost THIRD EXAMPLE of GMO: Salt-resistant tomatoes More tolerant to higher levels of salt in the soil Advantage – grow in different regions that have a high salinity content in the soil Advantage – help solve world hunger

FOURTH EXAMPLE of GMO: Production for Medical Treatment Some people's blood does not clot because they lack a protein called factor IX. Least expensive way for these people to get the protein they need is by producing large amounts of factor IX by using sheep. Sheep are transferred with the gene that makes protein/factor IX, and that gene is inserted in part of the DNA that codes for milk production. This milk now contains factor IX for human consumption. Gene for human protein factor IX GM sheep which synthesized factor IX Milk containing factor IX

GMO BENEFITS Improve food production Faster than selective breeding GM crops which produce their own pest-control substances; Less chemicals needed to help with pest control Help reduce hunger and GMO’s require less water Using GMOs to produce rare proteins for medications or vaccines; Cost-effective/Less pollution

GMO CONCERNS Unsure of long-term effects; Pollen from GMO’s may fall elsewhere (invasive/wild species) Corporate monopoly Risks for allergies Potentially harmful to humans Danger that genes could cross species. Decrease biodiversity

Clone: group of genetically identical organisms or a group of cells artificially derived from a single parent. Made using laboratory techniques Used in farming for decades Regenerating plant material In-virto fertilized egg to divide and make copies of itself Cloning was only possible in the beginning by using genetic info from an egg cell. Eggs are not differentiated yet (specialized) Cloning with differentiated animals cells Resulted in Dolly

Therapeutic versus Reproductive Cloning: Reproductive cloning – entire new individual such as the case of Dolly A somatic cell was taken from a donor (nucleus was removed). Nucleus was culture. An egg cell was taken from another sheep (nucleus was removed). Using electricity the nucleus was put in the unfertilized egg cell. Cell developed in vitro then placed in the womb of a surrogate sheep Therapeutic cloning – making copies of cells but not to make a new organisms Aim is to develop cells which have not yet gone through the process of differentiation Involves using embryos – stem cell research

Ethical issues with therapeutic cloning: Unnatural Immoral Benefits with therapeutic cloning: Growing skin to repair burns Growing new heart muscles to repair an ailing heart Growing new kidney tissue to rebuild a failing kidney

Topic 4.4 Genetic Engineering and biotechnology

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Topic 4.4 Genetic Engineering and biotechnology

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