How can I do a hair DNA test?
by admin on Friday, March 6th, 2009 | No Comments
Mark Cijo Jn asked:
A hair DNA test is normally performed when it is not possible to obtain the sample of the person to be tested using the standard oral swabs provided when you order your DNA test kit. DNA testing through oral swabs is by far the standard method of sample collection as it is very easy to peform; however DNA tests, such as paternity testing, can also be performed using other samples such as hair.
DNA testing through hair is one of the most frequently used forms of non-standard sample used. This is because obtaining hair samples can be simpler than obtaining other types of samples. For example, if a child lives abroad and it is difficult or time consuming to get a kit sent to him, then it is possible to send in the hairs directly for testing. Another example could be in the case of a deceased person, where it is possible to collect hair strands directly from the body before it is buried or cremated.
The ideal sample when using hair for DNA testing is normally a minimum of 5 strands of hair. Of course the more hair you send the more DNA can be extracted for testing purposes or, alternatively, the greater the number of tries that can be made to extract DNA if previous attempts are unsuccessful.
It is also critical that the hair has the root attached. If the root is not attached and/or the hair has been cut, then it will not be possible to use the sample for DNA tests such as paternity and relationship testing. The only testing that will be possible is for Mitochondrial DNA testing which is passed on from the mother to her siblings.
The age of the hair is also important. Freshly plucked hair has a much higher rate of success (in terms of DNA extraction) than older hair. This is not to say that you cannot extract DNA from older samples, however if the hair is older than a few months it is recommended that testing is done through extensive forensic methods as opposed to regular forensic extraction.
Therefore, when performing a hair DNA testing it is important to do the following:
Collect as many hairs as possible; Confirm the hairs have the root attached before sending; Do NOT touch the hair at the part where the root is attached or else you will contaminate the sample; Place the hair in a paper or plastic envelope and mark accordingly (ie that the envelope contains hair); Advise the lab of the approximate age of the hair (e.g. freshly plucked vs stored for over year)
It is also important to note, that once the DNA is obtained from the hair, the accuracy of the DNA test such as the paternity test, does not change. Therefore, using hair or a swab will not affect the accuracy of the result. The only factor that changes is the probability of extracting DNA from the sample.
If you intend to send in a hair for DNA testing we recommend that you advise the laboratory in advance, as well as obtaining a quote for the work, as normally there is an additional charge over and above the standard cost of the test for processing such a sample.
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A hair DNA test is normally performed when it is not possible to obtain the sample of the person to be tested using the standard oral swabs provided when you order your DNA test kit. DNA testing through oral swabs is by far the standard method of sample collection as it is very easy to peform; however DNA tests, such as paternity testing, can also be performed using other samples such as hair.
DNA testing through hair is one of the most frequently used forms of non-standard sample used. This is because obtaining hair samples can be simpler than obtaining other types of samples. For example, if a child lives abroad and it is difficult or time consuming to get a kit sent to him, then it is possible to send in the hairs directly for testing. Another example could be in the case of a deceased person, where it is possible to collect hair strands directly from the body before it is buried or cremated.
The ideal sample when using hair for DNA testing is normally a minimum of 5 strands of hair. Of course the more hair you send the more DNA can be extracted for testing purposes or, alternatively, the greater the number of tries that can be made to extract DNA if previous attempts are unsuccessful.
It is also critical that the hair has the root attached. If the root is not attached and/or the hair has been cut, then it will not be possible to use the sample for DNA tests such as paternity and relationship testing. The only testing that will be possible is for Mitochondrial DNA testing which is passed on from the mother to her siblings.
The age of the hair is also important. Freshly plucked hair has a much higher rate of success (in terms of DNA extraction) than older hair. This is not to say that you cannot extract DNA from older samples, however if the hair is older than a few months it is recommended that testing is done through extensive forensic methods as opposed to regular forensic extraction.
Therefore, when performing a hair DNA testing it is important to do the following:
Collect as many hairs as possible; Confirm the hairs have the root attached before sending; Do NOT touch the hair at the part where the root is attached or else you will contaminate the sample; Place the hair in a paper or plastic envelope and mark accordingly (ie that the envelope contains hair); Advise the lab of the approximate age of the hair (e.g. freshly plucked vs stored for over year)
It is also important to note, that once the DNA is obtained from the hair, the accuracy of the DNA test such as the paternity test, does not change. Therefore, using hair or a swab will not affect the accuracy of the result. The only factor that changes is the probability of extracting DNA from the sample.
If you intend to send in a hair for DNA testing we recommend that you advise the laboratory in advance, as well as obtaining a quote for the work, as normally there is an additional charge over and above the standard cost of the test for processing such a sample.
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