DNA profiling

DNA profiling

1. PROCEDURE: the DNA is obtained from individual, DNA is digested with a restriction enzyme which cut the DNA at the specific recognition sites into fragments, the fragments are separated by gel electrophoresis and stained, larger fragments travel the shortest distance in the gel. A banding pattern can be seen and the DNA to which the individual's is being compared to is treated with the same restriction enzyme and electrophoresis. The banding patterns of the DNA samples are compared

2. Types of DNA analysed: the first method involved restriction fragment length polymorphism analysis but this method is laborious and is no longer used. Now, short tandem repeat (STR) sequences of DNA are used, these are highly variable short repeating lengths of DNA. STR sequences are separated by electrophoresis- this method is very sensitive and even a trace of DNA left when someone touches an object can produce a result, samples must be treated carefully to avoid cross contamination

3. APPLICATIONS OF DNA PROFILING

   • FORENSIC SCIENCE: has aided the conviction of criminals and established the innocence of those wrongly convicted
   • Examples include: identifying Nazi war criminals in South America, refute claims that Anastasia is alive, identified Richard 3's remains
   • MATERNITY AND PATERNITY TESTS
   • ANALYSIS OF DISEASE
     • Protein electrophoresis can detect the types of haemoglobin present and aid diagnosis of sickle cell anaemia