# Why use hair for DNA tests?



## SunnyDraco (Dec 8, 2011)

Okay... I had a long explanation but it vanished right about the time I told it to post... Maybe it will show up later so then I become redundant LOL

Basically, the hairs that are pulled carry the DNA in the roots (which is why freshly pulled hairs with roots attached are required for hair samples submitted for testing). Can you imagine drawing and shipping blood? That should be left to the vets, not the curious owner wanting to color test and/or test for genetic diseases. 

As far as submitting DNA to a registry to find out if a horse is registered with them, I recommend calling the registry about it first. Last I knew, none of the registries who keep DNA on file for registered horses has the ability to compare a DNA sample to their entire list of horses with DNA on file. You likely need at least a name for them to compare with, either the sire's registered name, the dam's registered name or the registered name of the horse in question. 

The hair vs blood requested for tests depends on the test, various methods are used as some are more accurate one way or the other. I would place more faith in a vet diagnosing pregnancy with ultrasound machines than a vet using blood to test for pregnancy. Both methods can still be inaccurate to diagnose pregnancy.
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## QtrBel (May 31, 2012)

I would assume with a horse as it "should" be grazing on a continuous basis there is going to be too much interference from other "stuff" to use cheek swabs. You'd likely have to prep with a rinse then swab which makes it more difficult than a quick pull.


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## BiologyBrain (Jul 9, 2015)

SunnyDraco said:


> As far as submitting DNA to a registry to find out if a horse is registered with them, I recommend calling the registry about it first. Last I knew, none of the registries who keep DNA on file for registered horses has the ability to compare a DNA sample to their entire list of horses with DNA on file. You likely need at least a name for them to compare with, either the sire's registered name, the dam's registered name or the registered name of the horse in question.


The ABCR has a contract with one of the labs to check parentage. I think they did a study to see how many horses were incorrectly registered or something. I've of the Curly people I email chatted with suggested I submit samples. It's on the registry's webpage.


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## BiologyBrain (Jul 9, 2015)

QtrBel said:


> I would assume with a horse as it "should" be grazing on a continuous basis there is going to be too much interference from other "stuff" to use cheek swabs. You'd likely have to prep with a rinse then swab which makes it more difficult than a quick pull.


I guess that makes sense. We did studies with people in our lab & it didn't matter really if you'd been eating or drinking or not immediately before you were swabbed. Horses may be different. It just bugged me. :shrug:


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## SunnyDraco (Dec 8, 2011)

BiologyBrain said:


> The ABCR has a contract with one of the labs to check parentage. I think they did a study to see how many horses were incorrectly registered or something. I've of the Curly people I email chatted with suggested I submit samples. It's on the registry's webpage.


Parentage verification isn't against the entire database, it is against the particular parents to verify that sire and dam are correct by checking DNA. They parentage check purebred Arabians for registration but you cannot send in a sample to find out if your horse was ever registered with them or if they have the parents on file without having exact names of the registered horses. Ask the registry if they can take a sample and check it against their entire database, I am 99.9999% sure that the answer is no. However, if you want to check to find out if X horse is the son/daughter of Y registered horse, that would be possible.


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## Chiilaa (Aug 12, 2010)

I think the answer may be in logistics. Imagine you were in Australia, sending a sample to a lab in the US. Even by the fastest possible post, it takes a minimum of 72 hours, most things take at least a week to arrive. I think hair follicles would be the most stable DNA source for this sort of thing.


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## QtrBel (May 31, 2012)

Hadn't thought of that. I was just thinking about the sample and having to sort out horse cells from everything else. Stability may be an issue depending on prep. Prep costs so cost to test goes up. Hair DNA is cheapest all round and most stable.


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## DuckDodgers (May 28, 2013)

Whenever I've collected DNA cheek swabs from dogs to be tested (color testing and PLL testing in my case, through UC Davis and OFFA) the instructions have always said to keep the dog confined away from food, water, other animals, or any sort of chews such as rawhides or cattle hooves that were once part of another animal. This prevents contamination from other sources that may affect the testing results. With a dog it's pretty easy- I simply put mine in their crates for the recommended period of time. An hour or two I think. That's not quite so easy with a horse, especially if you have a group turnout situation. That would be my guess as to why hair would be a better option than saliva. Why hair is preferable to blood is quite obvious- drawing blood is a hassle, and shipping blood is probably even more of an ordeal. Pulling some hair is no big deal with most horses and anyone can do it.


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## Dreamcatcher Arabians (Nov 14, 2010)

Pulling hair can be done with or without the horse's cooperation. If the horse is acting up, just grab a few hairs and the horse pulls away, you still get the hair. In the case of a buccal swab, I have worked with horses whose mouth and or front hooves I wouldn't voluntarily get near. Not every horse is as cooperative or well trained as your personal horse.


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## BiologyBrain (Jul 9, 2015)

SunnyDraco said:


> Parentage verification isn't against the entire database, it is against the particular parents to verify that sire and dam are correct by checking DNA. They parentage check purebred Arabians for registration but you cannot send in a sample to find out if your horse was ever registered with them or if they have the parents on file without having exact names of the registered horses. Ask the registry if they can take a sample and check it against their entire database, I am 99.9999% sure that the answer is no. However, if you want to check to find out if X horse is the son/daughter of Y registered horse, that would be possible.


Apparently the ABCR is willing to run an unknown horse's DNA against their entire database. I contacted the organization via email & received instructions on which test to order. If I'm lucky, I'll find my rescue mare's parentage and maybe even her registered name - if she was registered before she was shipped to auction as a weanling. I'm really excited! Even if she's not in their database, I'll love her just the same.


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## BiologyBrain (Jul 9, 2015)

QtrBel said:


> Hadn't thought of that. I was just thinking about the sample and having to sort out horse cells from everything else. Stability may be an issue depending on prep. Prep costs so cost to test goes up. Hair DNA is cheapest all round and most stable.


In our forensic lab the order of preference for DNA standards was 1-blood, 2-buccal, and 3-hair. Blood and buccal standards are stable for a really long time as long as they're dried. Not all pulled hairs will have DNA attached & the DNA that is attached won't all be useful - according to our lab. Dried DNA standards (blood and/or buccal - even saliva or toothbrushes) have been used in some of my cold cases from 30+ years ago without degradation even if storage conditions weren't optimal (refrigerated, humidity controlled, etc). In our lab the prep of the sample regardless of type of DNA standard is the same basically (I think). If they're worried about picking up foreign DNA... I guess maybe they aren't using as effective of probes and amplifiers for the PCR. But it is a different application with much more highly developed probes and such used. 
Sorry, :hide: I'm such a nerd. 

I know some horses are harder to handle than others, but since presumably most people are handling their horses that they want genetic testing done on anyway, they'd be able to have the vet draw blood (since they're probably doing vaccines & a Coggins anyway) or tie the horse/keep it from eating for a while before sticking something in it's mouth (like a bit). Of course, pulling hairs is probably easier & I guess they have good luck with getting results from the hair. So, I guess it works out anyway.  

I'll pull the hairs requested and send them in. The. I'll hopefully know more about my mare's family history!


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## HombresArablegacy (Oct 12, 2013)

Some 20 years ago, blood testing was the norm for parental verification. This required 1. Having a vet pull the blood, requiring paying for a trip charge and fee for the procedure. 2. Because you had to take the blood work to the post office and mail it, it had to be done on a Monday, in order to insure it got to the lab before the weekend, otherwise the blood would go bad. ( Had that happen once, ended up paying double to repeat steps 1 and 2).

3. If you had to do it in the summertime, you had to worry about the sample going bad fairly quick.

The Arabian registry was one of the first breeds to approve DNA testing, which makes the whole process so much easier, just yank a hand full of mane with the root bulbs attached, stick it in an envelope, and wait for the results. And, as you know, DNA doesn't lie. 
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## DuckDodgers (May 28, 2013)

BiologyBrain said:


> In our forensic lab the order of preference for DNA standards was 1-blood, 2-buccal, and 3-hair. Blood and buccal standards are stable for a really long time as long as they're dried. Not all pulled hairs will have DNA attached & the DNA that is attached won't all be useful - according to our lab. Dried DNA standards (blood and/or buccal - even saliva or toothbrushes) have been used in some of my cold cases from 30+ years ago without degradation even if storage conditions weren't optimal (refrigerated, humidity controlled, etc). In our lab the prep of the sample regardless of type of DNA standard is the same basically (I think). If they're worried about picking up foreign DNA... I guess maybe they aren't using as effective of probes and amplifiers for the PCR. But it is a different application with much more highly developed probes and such used.
> Sorry, :hide: I'm such a nerd.
> 
> I know some horses are harder to handle than others, but since presumably most people are handling their horses that they want genetic testing done on anyway, they'd be able to have the vet draw blood (since they're probably doing vaccines & a Coggins anyway) or tie the horse/keep it from eating for a while before sticking something in it's mouth (like a bit). Of course, pulling hairs is probably easier & I guess they have good luck with getting results from the hair. So, I guess it works out anyway.
> ...


How many average Joes simply curious about their horse's color are actually going to go through the effort of calling the vet out/paying for a barn call? And go through the additional effort of shipping blood? I certainly wouldn't on a "want to know" basis, though were I breeding or concerned about a potential genetic problem in my horse I would suck it up. I'd also probably wind up forgetting to get the blood drawn for testing when I happened to have the vet out, but that's just me :icon_rolleyes: If I had to get blood drawn for my dogs' color testing then I probably wouldn't have had it done. It's a lot of extra steps and no information I NEED to have... just leaves the potential for color surprises in pups produced  

I also wouldn't be particularly inclined to wait around with a tied horse for a couple of hours simply to know. Much easier to do with dogs, just stick them in the crate for awhile! Sure, it CAN be done, but if you can get good results from hair just as well then I see no reason to go the blood or saliva route with horses. Maybe that's just me being nit picky about these things, but the average curious person isn't going to go TOO far out of their way to get testing done that isn't necessary. The average person likely being people that aren't really into horses and active on a horse forum


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## Dreamcatcher Arabians (Nov 14, 2010)

DuckDodgers said:


> How many average Joes simply curious about their horse's color are actually going to go through the effort of calling the vet out/paying for a barn call? And go through the additional effort of shipping blood? I certainly wouldn't on a "want to know" basis, though were I breeding or concerned about a potential genetic problem in my horse I would suck it up. ......
> 
> The average person likely being people that aren't really into horses and active on a horse forum


You have a real valid point there Duffy Duck. I AM breeding and active on this and other forums and I would not deal with having blood drawn. Since I can pull hair and send it in AND go back for up to 5 years for additional testing off of one sample, I have tested BOTH my mares for Red/Black/Agouti, LWO, Tobi, Splash and probably a couple more, just cuz. Well, LWO was a safety precaution but all the rest, just because I could. 

Genetic lethal testing I'd do either way, but since it can all be done off one pulling of the hair, how simple is that? No excuse not to have it done.


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## beatehs (Sep 3, 2015)

I have had a "paternity case" on one of my foals. 

We got the message from the lab that the registered sire could not be the sire. 

Result was that all the stallions on stud that day had to be checked for paternity. That was 22 stallions. None checked out! There were 4 more likely than the others, but no 100% matches. 

The solution was as simple as it was funny; the sire should be De Noir, but a typo had put the sire as De Niro, which is the father of De Noir. When they checked the DNA against De Noir it was correct. It was really very interesting! ?


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