Direct Biological Samples

Testing Biological Samples

When the paternity of child is in question the most accurate way to determine that paternity is through DNA testing. This scientific process will either confirm or eliminate the possibility of a biological connection between two individuals with near perfect accuracy. This is done through the genetic testing of DNA samples that are provided by each of the individuals in question.  

Direct Biological Samples

There are a number of different direct biological samples that can be used for the purpose of DNA testing. In most situations, a swab of the cheek is taken from each of the individuals involved in the matter of paternity. This is called a buccal swab and it is simple and painless method of DNA collection. Buccal swabs have quickly become the most popular method for collecting direct biological samples for the purpose of DNA testing.  

That said, situations do arise in which one party involved in a DNA dispute does not or cannot provide a buccal swab. In some cases the party is unwillingly to provide the direct biological sample. However, there are also situations in which a person may be deceased or absent, hence they are unable to provide a direct biological sample for DNA testing.  If this occurs there are a number of alternative direct biological samples that can be used. Those would include blood, hair, nails, bone, and sperm.  

Alternative Sample Types

Blood used to be the gold standard when it came to direct biological samples that are used for DNA testing. Samples of a person’s blood can be tested for DNA in many forms including drawn blood, blood on material, dry blood, and blood spots or splatters. When buccal swabs were introduced to the greater scientific community blood samples took a back seat to the lesser invasive procedure.

Hair can also be used as a direct biological sample for DNA testing. However, if hair is to be used for DNA testing it must have either the root or follicle attached to the sample. In addition to this, the sample needs to contain as much hair as possible, and it is essential to avoid contamination of the sample by handling the sample with gloves only.

Strange as it may seem nails can also be used as a direct biological sample. Nails have the same general properties that hair does which is why they can be used to extract DNA for testing. This is a sample commonly used when a person is recently deceased. It is best to use fresh nail clippings.

Another source for direct biological samples would be bone. These samples are not commonly used because they are difficult to collect. In fact, not all DNA testing facilities are even equipped to handle this type of DNA sample. Bone is only used as a sample for testing when a person is deceased.

Anyone who has watched an episode of CSI knows that sperm can be tested for DNA. Extracting sperm from a material is quite a process, for this reason it is rarely used when it is not necessary. In fact, direct biological samples of sperm are most commonly used in the investigation of crimes.