dna test question

metrovelvet

When someone takes in a swab test to a lab to confirm the parentage of a child, is the mother and the father's dna detected?

Do they file this information? Is it attached to a name or kept on record anonymously?

Where does your genetic information go?

Does dna expire? What can compromise the sample?

2Scoops

A DNA test for parentage can be used to identify both mother and father if necessary, since the child's DNA will be composed of sequences from both. It's actually easier to identify the mother because of mitochondrial DNA but it's usually the father that's in question.

Not sure about data storage but most human DNA-related work has to adhere to strict guidelines concerning privacy etc. Usually it's filed under an anonymous subject number but then something else would have to link the number to your name - but I believe the information has to be destroyed after a certain period of time too, depending on the place that's doing it. They are obliged to give you all this information so you could ask directly.

Stored properly, DNA does not really expire. Again, usually they have to incinerate samples after a certain period.

Compromising the sample would be difficult unless there was some kind of contamination at sample collection time. Collections have guidelines to prevent this from happening. If some foreign DNA got in there by accident and the analysis used PCR [a technique that replicates millions of copies of any DNA present] it would magnify the foreign DNA as well the intended DNA ruining the test - but in the unlikely event of this happening, it would be noticed anyway so it's a pretty solid test.

Marksie

actually dna paternity testing doesnt use mitichondrial DNA at all.

It uses the junk DNA between the genes and specifically highly variable repeated sequences found within them.

"traditional" multilocus fingerprinting uses enymatic digestion to chop up the dna which a probe is hybridised to to yield a "barcode" pattern

PCR based tests use str (simple tandem repeats), quite a few of them, to build up a profile. ( a single str yields a maximum of two amplicons, one from each chromosome pair). Each str is chosen so tha it is hyprevariable in a population..i.e lots of different ones in a population. You need this so that the chance of an str amplicon matching a random individual is low.

The DNA from swabs can last years if stored correctly.
analysis involves comparing teh mothers and fathers (though single parentage analysis is possible) to the childs.

A child gets 50% of its dna from the mother and 50% from the father roughly.

THus if you look at the amplicons in the mother and match it to the corresponding one from the child, whatever is left must come from the father.
If it is the same size as the fathers it is a match and indicative of positive paternity, if it doesnt then it came from somene else, and indicates negative paternity.

You dont do one str you do a whole battery of them to build this "profile"



The company will have strict guidelines ono storage and records under the data protection acts. You had better ask them
similarly with storage and labelling of samples.

The testing has a whole series of checks and balances built into it to enure that cross contamination and errors do not occur.
I have faced court situations where the minutaae, down to the written report has been examined.

It is proven technology and very reliable.

The advantage of PCR based techniques is that the sample can be in a terribly broken down state and still be useful.


Buccal swabs that you are talking about Metrovelvet use the cheek cells and are then posted off. The doctor taking the samples will sign the formsd ... actually when i did it, the doctor had to sign a passport photograph..or photograph of the people (including child) in the case

hope this answers some of your queries

this thread discusses the use of the same technology in forensics... it is very similar but a more in depth discussion
http://www.boards.ie/vbulletin/showthread.php?t=2055056599&referrerid=&highlight=

2Scoops

Marksie wrote:

actually dna paternity testing doesnt use mitichondrial DNA at all.

Never said it did:) I merely stated that the option of using it to identify the mother makes the process much simpler than paternity testing since it's inherited directly.