Reminder – deadline for W20 samples


I wanted to post a quick reminder that the deadline for having your horse included in the upcoming W20 study is this Tuesday, April 15, 2014. As mentioned in the previous post, the W20 mutation is one of the newly identified White-spotting (W) patterns. The majority of these patterns have been new mutations that originated in specific families of horses within the last few decades. The W20 mutation is different in that it has been found in a number of unrelated breeds (a current list can be found here), which suggests that the pattern is old. That means it may be widespread in the equine population.

Unlike the other patterns in the W series, this one does not put a lot of white on the horse – at least not unless it is paired with another pattern. The exact range of expression is not known, however, nor is it clear how it interacts with some of the other forms of white patterning. To better understand that, one of the research groups in Germany is offering the W20 test for a brief time. The idea is to both collect a range of samples and raise the funds necessary to do the work. (Horses, unfortunately, do not tend to attract third party research grants, so the biggest impediment to progress is lack of funding.)


Dr. Rony Jude, one of the scientists involved in this project, has indicated that the horses submitted need not be pintos, or even have obviously flashy markings. Horses like the two included in this post would be helpful. I have submitted my own Appaloosa mare, who has only a moderate blaze and a white hind pastern. Groups of related horses are also helpful. Other good candidates are horses that have known, tested patterns but that have more white than might be expected.

The (English-language) form needed to have your horse included is located here. Owners in the United States will need to send their samples in now in order to meet the deadline. For those that have not done genetic testing before, collecting samples involves pulling 30 tail hairs (the root bulb must be visible). For this study, each horse needs two samples: two ziplock bags of 30 hairs. I would also recommend sending the materials in a padded envelope – not a package – to avoid delays in customs. The form indicates that you need to submit three photos (both sides and a face shot showing markings) and a pedigree. Pedigrees are useful for finding possible sources for the mutation, but they are not required for inclusion in the study; you can submit unregistered horses. Dr. Jude has also set up a PayPal account ( for participants in the United States, where foreign bank transfers tend to be costly. The necessary photos and the form can also be sent to that address, which is a good idea since we are so close to the deadline.

I hope that Dr. Jude and her team get a good turnout for the study. With luck, W20 could prove to be one of the bigger pieces of the puzzle when it comes to understanding how white markings and white patterns work in horses.


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