Genetic Engineering – Topic 4.4

Reading: Clegg pgs 117-135; Campbell Ch 20

11/12Holiday

11/13Lecture

11/15Test: DNA/Protein Synthesis Review, Homework Packet Due

11/16H-Lab- Molecular Biology Tutorial

11/19Lecture; Biotechnology Articles and Questions

11/20Lecture

11/21Lecture

11/22Holiday

11/23Holiday

11/26 Lecture; assign Infectious Disease report

11/27Library- Infectious Disease report research

11/29Test: Genetic Engineering Review, Homework Packet Due

Genetic Engineering Topic 4.4

4.4.1 Outline the use of polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA

PCR is a way of producing ______of a specific target sequence of DNA

It is useful when only a small amount of DNA is available for testing

  • E.g. crime scene samples of blood, semen, tissue, hair, etc.

PCR occurs in a thermal cycler and involves a repeat procedure of 3 steps:

1. ______:DNA sample is heated to separate it into two strands

2. ______:DNA primers attach to opposite ends of the target sequence

3. ______:A heat-tolerant DNA polymerase (Taq) copies the strands

One cycle of PCR yields ______identical copies of the DNA sequence

  • A standard reaction of ______cycles would yield 1,073,741,826 copies of DNA (230)

4.4.2 State that, in gel electrophoresis, fragments of DNA can move in an electric field and are separated according to their size

Gel electrophoresis is a technique which is used to ______fragments of DNA according to ______

  • Samples of fragmented DNA are placed in the wells of an ______
  • The gel is placed in a buffering solution and an ______is passed across the gel
  • DNA, being ______(due to phosphate), moves to the ______terminus (______)
  • ______fragments are less impeded by the gel matrix and move ______through the gel
  • The fragments are thus separated according to size
  • Size can be calculated (in kilobases) by comparing against a known industry standard

4.4.3 State that gel electrophoresis of DNA is used in DNA profiling

  • DNA profiling is a technique by which individuals are identified on the basis of their respective ______.
  • Within the ______of an individual's genome, there exists ______

______- long stretches of DNA made up of repeating elements called ______

______(STRs)

  • These repeating sequences can be excised to form fragments, by cutting with a variety of ______(which cut DNA at specific sites)

  • As individuals all have a ______in a given sequence of satellite DNA, they will all generate unique fragment profiles
  • These different profiles can be compared using gel electrophoresis

DNA Profiling Using STR Analysis

4.4.4 Describe the application of DNA profiling to determine paternity and also in forensic investigation

Two applications of DNA profiling are:

  • ______(comparing DNA of offspring against potential fathers)
  • ______(identifying suspects or victims based on crime-scene DNA)

Paternity TestForensic Investigation

4.4.5 Analyse DNA profiles to draw conclusions about paternity or forensic investigations

Paternity Testing: Children inherit ______of their alleles from each parent and thus should possess a ______of their parents alleles

Forensic Investigation: Suspect DNA should be a ______with the sample taken from a crime scene if a conviction is to occur

4.4.6 Outline three outcomes of the sequencing of the complete human genome

The Human Genome Project (HGP) was an international cooperative venture established to sequence the 3 billion base pair (~25,000 genes) in the human genome

The outcomes of this project include:

  • ______:We now know the number, location and basic sequence of human genes
  • ______:This has allowed for the production of specific gene probes to detect sufferers and carriers of genetic disease conditions
  • ______:With the discovery of new proteins and their functions, we can develop improved treatments (pharmacogenetics and rational drug design)
  • ______:It will give us improved insight into the origins, evolution and historical migratory patterns of humans

With the completion of the Human Genome Project in 2003, researcher have begun to sequence the genomes of several non-human organisms

4.4.7 State that, when genes are transferred between species, the amino acid sequence of polypeptides translated from them is unchanged because thegenetic code is universal

The genetic code is universal, meaning that for every living organism the ______code for the ______(there are a few rare exceptions)

This means that the genetic information from one organism could be ______by another (i.e. it is theoretically transferable)

4.4.8 Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase

1. ______

  • A ______is removed from a ______(plasmids are small, circular DNA molecules that can exist and replicate autonomously)
  • A gene of interest is removed from an organism's genome using a ______which cut at specific sequences of DNA
  • The gene of interest and plasmid are both amplified using ______technology

2. ______

  • Cutting with certain restriction enzymes may generate "______" that allow the two DNA constructs to fit together
  • The gene of interest and plasmid are spliced together by ______creating a ______.

3. ______

  • The recombinant plasmid is inserted into the desired ______(this is called ______for eukaryotic cells and ______for prokaryotic cells)
  • The ______will hopefully produce the desired trait encoded by the gene of interest (expression)
  • The product may need to subsequently be isolated from the host and ______in order to generate sufficient yield

Treating Hemophilia via the Isolation of Human Factor IX Clotting Protein from Transgenic Sheep Milk

4.4.9 State two examples of current uses of genetically modified crops or animals

Crops

1. Engineering crops to ______of fresh produce

  • Tomatoes have been engineered to have an extended keeping quality by ______and thus delaying the natural process of softening of fruit

2. Engineering of crops to ______

  • ______(Bt corn) have been engineered to be toxic to the corn borer by introducing a ______from a bacterium (Bacillus thuringiensis)

Animals

1. Engineering animals to ______

  • Sheep produce ______when engineered with the gene for the enzyme responsible for the production of ______- the main amino acid in the keratin protein of wool

2. Engineering animals to produce ______

  • Sheep engineered to produce ______in their milk can be used to help treat individuals suffering from hereditary emphysema

4.4.10 Discuss the potential benefits and potential harmful effects of one example of genetic modification

Example:Maize introduced with a bacterial gene encoding a toxin to the European Corn Borer (i.e. Bt Corn)

Potential Benefits

  • Allows for the introduction of a characteristic that ______within the gene pool (selective breeding could not have produced desired phenotype)
  • Results in ______(requires less land for comparable yield)
  • Less use of ______, reducing the economic cost of farming
  • Can now grow in regions that, previously, may not have been viable (reduces need for ______)

Potential Harmful Effects

  • Could have currently ______(e.g. toxin may cause allergic reactions in a percentage of the population)
  • Accidental release of transgenic organism into the environment may result in competition with ______
  • Possibility of ______(if gene crosses the species barrier and is introduced to weeds, may have a hard time controlling weed growth)
  • Reduces genetic variation / ______(corn borer may play a crucial role in local ecosystem)

4.4.11 Define clone

A clone is a group of ______organisms or a group of cells derived from a ______

4.4.12 Outline a technique for cloning using differentiated animal cells

______(SCNT) is a method of reproductive cloning using differentiated animal cells

  • A female animal (e.g. sheep) is treated with ______(such as FSH) to stimulate the development of eggs
  • The ______from an egg cell is removed (enucleated), thereby removing the genetic information from the cell
  • The egg cell is ______with the nucleus from a somatic (body) cell of another sheep, making the egg cell ______
  • An ______is delivered to stimulate the egg to divide, and once this process has begun the egg is implanted into the ______of a surrogate
  • The developing embryo will have the ______as the sheep that contributed the diploid nucleus, and thus be a clone

Different Uses of Cloning

4.4.13 Discuss the ethical issues of therapeutic cloning in humans

Arguments for Therapeutic Cloning

  • May be used to cure serious diseases or disabilities with ______(replacing bad cells with good ones)
  • ______may pave the way for future discoveries and beneficial technologies that would not have occurred if their use had been banned
  • Stem cells can be taken from embryos that have ______and would have died anyway (e.g. abortions)
  • Cells are taken at a stage when the embryo has ______and can arguably feel no pain

Arguments Against Therapeutic Cloning

  • Involves the ______and ______of human embryos (at what point do we afford the right to life?)
  • Embryonic stem cells are capable of continued division and may develop into ______and cause tumors
  • ______embryos are generally produced than are needed, so excess embryos are killed
  • With additional cost and effort, alternative technologies may fulfill similar roles (e.g. ______

______of differentiated cell lines)