MG (DNA Profiling)

• repetitive sequences of DNA introns • They all feature the same core sequence. GGGCAGGAXG (X can be any one of the 4 nucleotides). • Lengths are highly variable -VNTRs (variable number tandem repeats)

hair pin structures on the end of chromosomes

• Extract DNA from sample - Can use PCR if the sample is small • Digest the sample – DNA cut into small fragments with restriction endonuclease • Separate the DNA fragments using electrophoresis. • Banding pattern is produced. • The DNA to which the individual is being compared is treated with the same restriction enzymes and is also subjected to electrophoresis • Banding patterns can then be compared

No. Varies from person to person.

electrophoresis

having more than one form – may refer to variations within the DNA sequences of a particular gene.

• very sensitive, and even trace DNA left when someone touches an object can produce a result • DNA samples can be stored for many years if a crime case is unsolved

samples have to be treated carefully to avoid contamination

• conviction of crimes • Proving innocence • Used in immigration cases to prove or disprove family relationships • paternity testing

• half of a child’s STRs are from the mum, half from dad so comparing DNA profiles of mother, father and child can establish maternity/paternity

• protein electrophoresis can detect type of Hb present and help in diagnosis of sickle cell anaemia • varying no. of repeat sequences can be detected by electrophoresis