HOW GENETIC PROFILING IS USED TO IDENTIFY CRIMINALS AND TO DO PATERNITY TESTS.
Leicester University (UK) geneticist Alec Jeffrey’s developed a technique called DNA fingerprinting in 1985. This technology, which has become known as DNA profiling, can be used to identify individuals. Modern-day DNA profiling is very sensitive technique which only needs a few skin cells, a hair root or a tiny amount of blood or saliva.
Paternity testing is the study of cells of the alleged father and the child through DNA tests that reveal whether there is genetic relationship between these two people by the similarity that must exist between both samples and confirm or deny paternity. The man, having sexual reproduction inherits an allele from the father and one from the mother. A child has for each locus an allele from the father.
The DNA analysis process consists of the following steps
v Extraction: Using any cell possessing core DNA can be obtained either from a drop of blood, hair or saliva are sufficient. To process these samples, reagents that disrupt cell membranes and release the DNA contained there, cleaning of wastes such as proteins and other organic compounds are added.
v Amplification: Once selected DNA fragments of interest, through a technique called Chain Reaction (PCR) fragments selected multiply, garnering millions of copies.
v Electrophoresis: Using an electric shock fragments amplified with the help of powerful automated equipment are separated, the results are displayed in the form of bands or peaks.
v Comparison: the sequences obtained in a given sample with another sample of DNA matches and observed to see if both sequences belong to the same person are compared, are father and son, or have no relationship.
Jeffrey’s study the gene of a protein called haemoglobin along this gene regions appear to differ between individuals. Differences were visualized by indirect methods, in form of strips of various sizes. Found that these regions varying in size between individuals they were scattered throughout the genome and that from them, could be defined what he called a "genetic fingerprint." This “genetic fingerprint “is personal and unique to each subject, except this rule to identical twins. Also noted that each individual half of the bands came from the mother and half from the father’s genetic fingerprint facilitates the identification of each individual (only share identical twins). However finding, "DNA" at the scene of a crime does not mean identify who committed the crime.
1-Recognition of samples: is essential to preserve the site of the fact any contamination wearing gloves, bloodstains, hairs, cigarette butts, guns, knives or other utensils that might have been used, etc. are collected.
2- Retests: if the gene has been altered shows the tests are repeated.
ADVANTAGES AND DISADVANTAGES AND CONCLUSION
- Comparison and identification of people in high risk professions such forces personnel and law enforcement, military, fire... or in case of accidents, fires or disasters.
- Children adopted or conceived through assisted reproduction using donated gametes. These people do not share a genetic code with their parents, so studies comparing DNA can not be used with parents or other family members when carrying out a biological identification in case of accident, fire, kidnapping or other situations doubts which may exist at the time of carrying identification.
- Provide information for future testing relationship, since they are based on the comparison of genetic profiles.
- In conclusion, this new technology his really important for identification because we have different ways to differentiated from other person or to know who is so similar genetically to us that is consider our parent.