Applications of DNA Profiling
- Genetic Screening: detection of inherited diseases.
- Parenthood Disputes: establishing
- Crime Investigation: rape, murder or was the suspect at the scene of the crime.
- Animal Pedigree Check
- Archaeological: check relationship between human remains in archaeological sites and people alive today.
DNA (Genetic) Screening
Genetic screening is a test to determine if an individual carries an abnormal gene for a particular trait.
Genetic screening can also tell if the individual is homozygous normal, homozygous abnormal or heterozygous.
Special genetic probes or DNA profiling may be used in genetic screening.
RNA - ribonucleic acid
- Three different types of RNA, (messenger, ribosomal, transfer) and all are Applications of DNA Profiling involved in protein synthesis.
- mRNA: copies the information from the DNA.
- rRNA: each ribosome is composed of roughly equal parts RNA and protein.
- tRNA: carries the specific amino acids to the mRNA in contact with the ribosome.
Some RNA molecules can function as catalysts.
Differences between DNA and RNA
- DNA is a double polynucleotide strand; RNA is a single polynucleotide strand.
- DNA contains the sugar deoxyribose; RNA contains the sugar ribose.
- DNA has thymine base but not uracil; RNA has uracil base but not thymine.
- DNA is self-replicating, RNA is copied from the DNA so it is not self-replicating.
Mandatory Applications of DNA Profiling Activity
Isolation of DNA from Plant Tissue
Textbook Diagram: DNA isolation from plant tissue.
- Make up a salt and detergent solution in water.
- The detergent breaks up the cell membranes setting free the chromatin.
- The salt protects the DNA from the phosphates of the cell membranes.
- Mash a small piece of fresh onion with a glass rod in a beaker.
- The mashing breaks the plant cell walls releasing the chromatin into the liquid.
- Decant the liquid, containing the chromatin, from the pulp into a clean test tube.
- Add a protease to the liquid. The protease digests the protein of the chromatin Applications of DNA Profiling freeing the DNA.
- Slowly pour freezer-cold ethanol into the test tube and let it stand for a short time.
- A cold ethanol forms a separate layer on top of the DNA solution.
- DNA is insoluble in ethanol and so it precipitates out at the boundary as fine whitish threads.
- At the boundary twirl the roughly scratched end of a glass rod or twirl a small wire loop.
- A sticky gel-like material is collected – this is DNA.
Characteristics: eukaryotic, heterotrophic, cell wall of chitin.
Distribution: mostly terrestrial, living in soil; some can be found in freshwater Applications of DNA Profiling and a few are marine.
- Saprophytic: feed on dead organic matter e.g. Rhizopus.
- Parasitic: live with and feed off another living organism causing it harm, e.g., potato blight fungus.
Textbook Diagram: vegetative structure.
- Hypha: a tubular filament growing at its tip, new hyphae form by branching.
- Mycelium: all the hyphae together making up the vegetative mass of the fungus.
- Stolon Hyphae: horizontal hyphae growing across and colonising the food environment.
- Rhizoidal Hyphae: penetrate the solid medium anchoring the fungus.
- Sporangium: a vessel in which the spores are formed and are released for wind dispersal.
- Sporangiophore: a hypha carrying Applications of DNA Profiling a sporangium.
- Columnella: a cross wall separating the spores from the sporangiophore, aids spore release.
- Apophysis: a swelling beneath the sporangium.
- Spores: unicellular asexual reproductive and dispersal agents.
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