Genetic Testing Dna Test Aflp

DNA testing has become a common procedure in criminal justice, health and family applications. Since 1985 when the term genetic fingerprinting was coined by British scientist Alec Jeffreys, many new types of genetic testing have become available. One increasingly popular method is amplified fragment length polymorphism or AFLP. AFLP is a type of polymerase chain reaction (PCR) test, which is considered superior to other methods in these key areas:

  • cost
  • discrimination
  • labor intensiveness
  • reproducibility
  • speed.

Understanding DNA and Genetic Fingerprinting

DNA is short for deoxyribonucleic acid and contains all the information about the way living things develop and function. It is composed of four nucleotide bases:

  • adenine
  • cytosine
  • guanine
  • thymine.

These nucleotides join in base pairs to create the ribbon like strands of our DNA. More than 99 percent of human DNA is identical. Only one tenth of one per cent of our DNA accounts for all that make us each person unique. It is this portion that is used in DNA testing to create a person’s individual DNA profile. DNA samples can be obtained from:

  • blood and other bodily fluids
  • hair
  • skin
  • other tissues.

How AFLP Works

AFLP uses restriction enzymes to digest DNA. Selected DNA fragments are amplified with PCR primers and then separated through the use of a gel. This all helps the genetic material to be seen more easily. AFLP allows DNA analysis without prior knowledge of nucleotide sequences. It can also detect polymorphisms in many different genomic regions at the same time.

AFLP Testing Applications

AFLP is especially effective for finding variations in very similar DNA. Because of this sensitivity, AFLP is widely used in studies of closely related:

  • animals
  • bacteria
  • fungi
  • human populations
  • plants.

AFLP testing is also used in criminal investigations and paternity tests. In the field, an AFLP test kit can be used to help identify a crime victim who can no longer speak for himself. This type of testing analyses 13 regions (or loci) of DNA. The chance of any two people being identical in all 13 regions is less than a one in one billion.

Other DNA Tests

Most early genetic testing relied on a technique called restriction fragment length polymorphism (RFLP). RFLP used a restriction enzyme to isolate repeating DNA sequences. Since that time, more sensitive and cost effective PCR tests such as ALFP have become more popular. Some other widely used DNA test methods include:

  • mitochondrial DNA analysis (DNA passed from mother to child).
  • STR analysis (Short tandem repeat)
  • Y-chromosome analysis (DNA passed from father to son only).

Ethical Questions

While the discovery of DNA testing has benefited both criminal justice and medical practice, it has also raised some ethical questions. Genetic profiling and storage may have serious implications in the areas of:

  • employment
  • health and life insurance
  • ownership and rights to DNA
  • possible uses of stored DNA
  • privacy.

Resources

Informa (2008).Amplified Fragment Length Polymorphism. Retrieved September 1, 2008, from the Informa Web site: http://www.informaworld.com/smpp/content~db=all~content=a713544747~tab=content.

Keygene (2008).AFLP Genetic Fingerprinting. Retrieved September 1, 2008, from the Keygene Web site: http://www.keygene.com/keygene/techs-apps/index.php.

President’s DNA Initiative (n.d.).History of Forensic DNA Analysis. Retrieved September 1, 2008, from the USA.gov Web site: http://www.dna.gov/basics/analysishistory/.