# DNA Testing



## Kadi Thingvall (Jan 22, 2007)

I got another DNA certificate in the mail today from AKC for one of my imports. 

I know you can compare the certificates to determine if two dogs are the parents of a pup, but can you also compare them to see how "related" two dogs are? Statistically, although probably not very common, it would be possible for two littermates to have very few to zero alleles in common (ie mom is AB and dad is CD so pup1 is AC and pup2 is BD, yes I realize this is just one pair out of many but you can extend this out over the entire 13 provided). So would the certificates tell me that certain pups in a litter are more closely related then others? Would I be able to use the certificate to determine which pup in the litter was most closely related to a grandparent?

Would it be reasonable to expect that you could use the results from these test to try to predict outcome of future breedings?

What if I have two dogs that are cousins, will comparing their certificates tell me that they are very closely related (genetically) cousins or only barely related at all? How many alleles would you expect to see in common before you called it a close relation?

Could uniformity of a litter be predicted by using the certificates? 

IE, are there really any uses for these certificates other then "yes, that's the sire/dam of my pup"?


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## Maren Bell Jones (Jun 7, 2006)

Strictly speaking in terms of genetics, all mammalian offspring in a litter should have the same coefficient of relatedness if they were sired by the same father. The coefficient of relatedness is a metric that population and behavioral biologists use to determine things like social behavior and altruism, like the classic Beldings ground squirrels who are more likely to alarm whistle for a close cousin or aunt than an individual who has a smaller coefficient of relatedness. So they are all equally related to each other, though not genetically identical, I guess is what you were asking. 

That being said, I'm not sure what the certificate from the AKC tells you as I haven't seen one. I don't recall how many total genes there are in dog DNA, but the only way you could get pups that are completely "unrelated" in terms of pup 1 being ABCDEFGHIJ etc (i.e.-have all dominant alleles) and pup being abcdefghij etc (i.e.-all recessive alleles) is if you mate an animal that was 100% homozygous dominant with an animal that's 100% homozygous recessive. Since some genes are fatal if they are one way or the other, that's not possible let alone statistically, the likelihood of that happening is pretty much not there. So two pups could be totally different for a few loci, but not _all_ of them.

Even if they are genetically exactly identical, like true identical twins, they can still be (and usually are) epigenetically (and therefore phenotypically!) different. Epigenetics tracks changes due to the environment "above the gene" and this is why even cloned animals or identical twins don't look exactly the same or why one animal from a set of twins might get a genetically derived cancer and die and the other animal may remain healthy. These are due to methyl groups silencing or turning off genes (called DNA methylation) or acetylation or deacetylation making the genes unwind from their histone proteins, making them more or less accessible. There are likely other mechanisms which are just being discovered. Epigenetics is cool stuff! This is a neat set of videos that explain epigenetics in lay terms and epigenetics in general should be of interest to breeders:

http://www.pbs.org/wgbh/nova/sciencenow/3411/02.html

So to answer your questions (maybe):

_ Would it be reasonable to expect that you could use the results from these test to try to predict outcome of future breedings?

_I haven't seen a certificate. Could you perhaps scan and post one? I'm not sure what they say. But I would say that perhaps you could to a degree, depending on what loci they matched.

_ What if I have two dogs that are cousins, will comparing their certificates tell me that they are very closely related (genetically) cousins or only barely related at all? How many alleles would you expect to see in common before you called it a close relation?_

The coefficient of relatedness of cousins is 12.5%. See:

http://taumoda.com/web/PD/library/kin.html

Now, that doesn't mean that only 12.5% of their DNA is the same (because, as we all can quote, we share like 95% of our DNA with a banana or whatever). I suspect they'd have to compare the entire genome to see, or perhaps use something like DNA microarrays to see which genes are being up or down regulated in common. DNA microarrays cost several thousand dollars a sample, btw. 

_ Could uniformity of a litter be predicted by using the certificates? 

_No, probably not. Even without considering epigenetics and the huge effect that it has, even on twins, you'd still have to compare every single loci of interest.
_
IE, are there really any uses for these certificates other then "yes, that's the sire/dam of my pup"?_ 

Probably not. But I'd still be interested in seeing it.


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## Michelle Kutelis (Sep 28, 2006)

I don't think there is much use for the info they have provided beyond "this dog is the sire or this dog is not the sire." (Or dam in your case, I assume this is my girl )

DNA testing could provide more info, such as how closely the cousins genetic material resembles each other, but I believe the registries use it simply as a genetic identification for the dog in question. 

Now I have heard of some of the other DNA testing places offering tests for certain things- i.e. vWD. THEY actually show through the DNA if the dog has the chromosomes that cause these things to be expressed.

But, I don't really know anything about the DNA program with AKC.


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## Kadi Thingvall (Jan 22, 2007)

The AKC DNA test does report only 13 markers. I don't know if this tells you more but then are 
PEZ01, PEZ03, PEZ05, PEZ06, PEZ08, PEZ12, PEZ20, UCB2010, UCB2054, UCB2079, PEZ16, PEZ17, PEZ20

There is a sample certificate online
http://www.akc.org/images/dna/certificate_analysis.jpg
It's hard to read the marker names, which is why I included them above in the order they are given. The last one is actually labeled GEN and is the gender of the dog in question, as a quality control measure.

And this page is from the company actually doing the testing
http://www.mmigenomics.com/products2b.html

I know with the parents each pup gets 1 allele from each parent on each spot. So I guess my question was more aimed at grandparents. I'll only deal with one marker, but expand it out to all 13.

dam - AB sire - CD
pup1 - AC

pup1 is bred to dog1 - EF

pup11 - AE
pup12 - CE
pup13 - CF

Would we be able to say, if this trend continued across the marjority of the 13 markers, that pup12 and pup13 are more closely related to their grandsire then pup11 is? Or are there not enough markers to use for this type of determination?

If there is value in this test above and beyond just "yes this is my pups parents" I'd actually consider testing more of my dogs. But if it's just a parentage tracking thing, why bother. I did the breeding, I know who the parents are, I don't need to pay AKC $$ to figure that one out.

Kadi


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## Jeff Oehlsen (Apr 7, 2006)

Not dealing with the ABC side of it, the only time I have seen a "throwback" as that is what non ABC genetic people call them is when the stud is eminantly prepotent, or is heavily linebred on.

This is why I truely do cry BS with pedigrees with G'Bibber, as I have looked at really heavily linebred pups and seen no sign of any physical characteristics, not have I seen any "style" in the work.

The few throwbacks I have seen without heavy heavy linebreeding cause me to think that it is an anomole, and not something that you could plan for at this time with the information I have seen available at the time........unless you were willing to spend an extrordinary amount of money.


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