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DNA Paternity testing with hair

Updated on July 23, 2013

Do you know why hair may not be the best sample to test for DNA?

This lens describes the structure of the hair and its uses in DNA testing for paternity. On the whole, hairs are not the best sample to use.

The main component of hair is keratin- a protein. Proteins are just globular structures and do not in themselves contain any DNA.

In some cases, using a sample such as hair is the only option however, for hair to be used in a paternity test, there are certain requirements.

A Hair DNA Sample for a Paternity Test

Hair is a long, slender structure which is composed of a protein known as Keratin. Hairs have a root which is embedded in the skin.

This root is sometimes called the hair follicle. The part of the hair which protrudes or exits the root and which we see with our naked eyes is the hair shaft.

In terms of DNA there is some DNA in the shaft of the hair; however, it is often not possible to fully extract it from the hair as it is present in very small quantities.

When the hair has the root or follicle, then it becomes possible to extract DNA as nuclear DNA is often plentiful in this part of the hair. Once the DNA is analyzed and extracted from the hair, the process of DNA examination destroys the hair.

DNA hair testing for paternity

DNA hair testing for paternity
DNA hair testing for paternity

If you want to use hair for a paternity test hair DNA Test you will need to make sure that the follicle is attached.

So basically, you take the hair and examine it closely- the follicle looks very much like a small white ball at the end of the hair.

If you have found the hairs in the shower, taken hairs that have been cut or and naturally shed hairs, rest assured that these will not be suitable for a paternity DNA test.

Hairs that have been plucked or pulled out are fine. If you do have these hairs and a minimum of 4-5 then you can send in these as a DNA sample.

We now need to consider the success rate of DNA extraction
We now need to consider the success rate of DNA extraction

We now need to consider the success rate of DNA extraction

Once scientists have the hair they will then need to go on and extract DNA from it. The chance of successful DNA extraction with a hair sample is around 60%. Once DNA is extracted, the percentage inclusion or exclusion for paternity remains the same- it does not change. If the tested man is the biological father the inclusion will be higher than 99.9%. If the tested alleged father is not the child's biological father he will be excluded with a clear 100% probability.

Hairs that have been removed via waxing and attached to a waxing strip will also not do for the test as the wax makes it rather difficult to remove the hair without damaging it and in some cases, certain chemicals in the wax may alter the DNA.

Ideally, there are better samples which can be used. However, when there is no other sample available that offers a higher success rate than hair then this will of course, be the sample to use.

Maternal Ancestry and Lineage
Maternal Ancestry and Lineage

Other uses of analysing hair samples

Well hairs that do not have the root and only the hair shaft can be used for a very special kind of DNA test. The shaft of the hair does not contain the usual DNA we use for genetic health tests and paternity tests; but it does contain another type of DNA which we call mitochondrial DNA. We all have mitochondrial DNA in our cells and we inherited this DNA from our mother. You have inherited this from your mother but you will pass it on to your children only if you are a female (to be said that both males and females inherit mtDNA from their mother).

This type of DNA is inherited unchanged for hundreds of generations. All people from the same maternal ancestral line will share the same mitochondrial DNA profile. This means that you can trace your origins by testing this very specific component of your genetic make up.

Info Site with all the necessary information about paternity testing

This info site explains anything from how to collect your DNA samples to the difference between at home paternity testing and legal testing.

Analysis of DNA
Analysis of DNA

Other options available besides hair

Learn the other possible forensic samples that can be used for DNA testing

We have already discussed that hair offers a success rate of around 60%. This is not exactly a very high success rate. Moreover, the chances of successful DNA extraction very much depend on the age of the hair and how that sample has been stored. It is definitely worth considering other samples which might be readily available and which offer a higher success rate. A used kleenex would be an ideal sample. It offers a success that is much higher than that of hair - around 95%. It is also not too hard a sample to collect. Nail clippings are also a good sample to collect and have a success rate of around 70%.

The important thing with nails is their age - ideally they should be not more than a week old. Cigarette ends are another relatively good sample with a success rate that is a bit higher that that for hair (around 65%).

Always make sure you get all the information you need about any DNA sample. DNA testing companies are there to assist you so make sure to get their advice prior to sending any samples. In my experience, they can often recommend a better sample than the one you have in mind or they might altogether recommend a different test.

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      anonymous 4 years ago

      @starfish26666 - that is exactly what I WAS THINKING! In movies they always use hair for DNA testing. LOL, goes to show that you should not get your info from movies, it is not dependable!

    • starfish26666 profile image
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      starfish26666 6 years ago

      funny how in detective films and the likes it is always that hair that gets picked up and used for DNA analysis. It lead many people to be misled and think that it is a viable sample for a DNA test