How Is DNA Fingerprinting Done?

Introduction

DNA fingerprinting is a process that involves the identifying and evaluating of a person's genetic material (DNA). DNA fingerprinting has a host of different uses including paternity testing, crime scene forensics and the identification of a decayed or destroyed body. Lately DNA fingerprinting has further to create a DNA database. Traditionally fingerprints have been used for identification purposes in this manner; However, DNA is much more accurate way to determine identity.

Vein

DNA fingerprinting can be done either through blood samples from a vein, or the use of a heel prick. DNA fingerprinting done through a vein sample is no different than getting a regular blood test done. A needle is inserted into a vein, and blood drawn into a sample container. The blood sample can then be sent off to a laboratory for DNA testing.

Heel

A less invasive way to perform a DNA fingerprinting is through a heel stick. The heel stick method is most commonly used when getting a DNA sample from a young child or infant. This provides a safe alternative to blood being drawn from a young child, and also limits pain and discomfort. A heel prick is done by pricking the heel with a lancet. The blood that is expelled from the wound is collected and sent to a DNA laboratory.

Other Collection

For DNA fingerprinting to be done for crime scene forensics or body identification, DNA samples can also be obtained through dried blood, semen, saliva, urine, hair, bone, teeth and skin. Bone and teeth DNA sampling is usually only reserved for body's that the skin has reached to great of a level of decomposition to give back an accurate result.

Result

Once the sample has been sent to a specialized DNA laboratory, the sample is placed through a series of tests to evaluate and identify the specific DNA regions, often referred to as DNA markers. To do this, scientists uses specialized probes that enter the DNA sample and bind to specific DNA sequences. The binding of these different probes to specific markers slowly paints a unique genetic picture of the individual.

Use

When two sample of DNA are compared, it is not completely uncommon for some DNA markers to match, even if the sample are not from the same person. However, if four or five DNA region markers match, it can safely be said that the sample is from the same person. This allows the scientists to determine everything from paternity to whether or not a person was present at a crime scene.

References

• The Human Genome Project