Parentage qualification and individual horse identification are only two of the possible uses for DNA-based testing. Below is an overview of how to interpret a test result in the basic sense.
"DNA" is just an abbreviation for the chemical "deoxyribonucleic acid". And genes are complex molecules of DNA which occur within each of every horse’s chomosomes. Most horses have 64 chromosomes, which are found in the nucleus of their body cells. Thirty-two chromosomes are inherited from the sire, and thirty-two are inherited from the dam. While chromosomes can be seen with a microscope, individual genes cannot. There are thousands of them, which range from those that affect coat color to those that affect behavior. Also included are genes called "microsatellites", which are a little different from those associated with inherited characteristics. Because they do not at this time appear to be responsible for any genetic traits of importance, microsatellites are sometimes referred to as "junk" DNA. They are nonetheless quite handy for making comparisons to presumed parent stock.
Microsatellites are also called "STRS" (an abbreviation for "short tandem repeats"). It is these "repeats" (the number of times and the order in which they appear) that are tested for and reported on the horse’s DNA test results.
15 specific "microsatellite DNA markers" have been assigned designations and have been internationally agreed upon by equine genetic testing laboratories. There are 5-12 possible variations at each marker site. The names of which ones, where, and how frequently they appear is designated by the letters and numbers seen on the report. Each letter is simply an abbreviation, or code, with a slightly more intricate meaning. The letter combinations (ASB23, et al) refer to the marker site and the numbers refer to the number of times that particular sequence of DNA sub-units repeats itself at that marker site.
Alpha characters are also used to identify the variation applicable to the horse in question. (Two at each site, one inherited from each parent. Some laboratories will only designate one alpha character at a specific marker site when the two variations are the same. For example, one Laboratory might specify "N/N" at a given site, while another reports it as a single "N").
Thanks to the International Society for Animal Genetics, laboratories converted to an International Standard in the late 1990's. Because of this, it is possible for one laboratory to make comparisons based on the parent information provided by another laboratory, so long as both laboratories have tested at least 10 marker sites in common.
Parentage qualification is based on Mendalian Genetics Laws that:
1) No offspring can inherit any factor unless at least one of its parents had that factor.
2) A proposed parent must be excluded if it does not share a genetic marker with a foal that has been assigned to it.
It needs to be understood that DNA hair sample analysis cannot verify that a particular horse is a Kiger when parent data is unavailable. Nor does it "prove" a given horse has a certain parent. What DNA hair sample analysis can do is determine whether or not a horse that is assumed to be a parent meets the criteria. This is why the term "parentage qualification" is used instead of "parentage proof". However, an incorrect parent may be excluded with 99% accuracy.
DNA may be obtained from almost any bodily tissue, but hair samples have proven to be the easiest to provide. Simply pull approximately one inch of mane hair with the follicle, or "root" attached. It is the follicle, not the hair shaft, that is tested, so it is very important to pull the hair from the root! Many times hair samples have been rejected by a laboratory because the submitted sample was cut, not pulled.
If you have previous records at one laboratory, and are now testing offspring at another laboratory, it is NOT necessary to re-test your breeding stock. However, whichever lab you choose to use will need to be supplied with the previous data on parent horses, regardless of where those parents were tested. That data must be in the form of copies of orginal lab reports. Handwritten data will not be accepted.
Also, records prior to 1999 may not have been converted to the International Standard, so that bridge may need to be crossed first in order for a laboratory to complete an accurate comparison.
In the case of horses obtained through BLM adoption, there is no parent record to make a comparison to. Those who test adopted horses from Kiger or Riddle Herd Management Areas are creating a base file for future reference.
DNA testing is strongly encouraged by the Steens Mountain Kiger Registry. It may be required if other documentation is unavailable or conflicting. The utilization of DNA parentage testing by breeders is strongly recommended, and we suggest that all buyers insist on a DNA record when purchasing a ranch-raised Kiger.
Test results from any certified laboratory can be accepted, so long as a parentage comparison has been made. However, it is far easier for breeders to maintain their records at one laboratory. SMKR has a contract rate of $36.00 through Stormont Laboratory, and the majority of the SMKR horses already tested are on file with Stormont. The advantage to using Stormont is that no kit is required, and owners can submit samples themselves and receive the results directly from the lab. Their submission form is located at their website. Specify "SMKR contract" when submitting, in order to get the contract rate.
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