A lot of doodle breeders are turning to Embark for their trait/health testing. If you've sent a test off recently you've seen a new Locus on your results.....the I Locus. Just when you thought you had a grasp on the trait results, they throw a new one in!
The I Locus is fairly new across the board, with other companies like Canine Health Check having had it for a little over a year now. But it is brand spanking new to Embark. Hopefully they'll update their chip data and all your older tests will be updated soon (like when they FINALLY added the S Locus).
So what is the I Locus?
It's referred to as Intensity...thus the "I". Its just one mutation they've found to explain the dilution of the phaeomelanin in some dogs. Big words, I know. So the simple version, it will give you some insight into the shade of “red” (phaeomelanin) hair the dog has or can produce. (It's important to note....this is only one mutation and with all the different shades of "red" out there, there is more than likely multiple mutations/genes responsible for the final outcome.)
This "shade of red" I speak of could refer to an e/e (recessive red) dog or an A locus patterned dog (sable, phantom). Examples of shades being: mahogany red, apricot, cream, white.
How is this helpful? I mean, you can see what shade the dog is. How is a test result going to help with breeding? Well here's the thing...you can see what shade an e/e dog is but how do you know what shade of red a black dog will produce if it carries for it? With this test, you'll have a better idea!
Here's the genotypes you could receive back and their meanings:
I/I- The dog has intense pigment. There’s no mutation found to lighten the color. This dog will be or carry the darkest shades of "red". So this will be your mahogany red or deep copper pointed dogs.
I/i- The dog has one copy of the mutation causing lighter pigment. It appears that the I allele is incomplete dominant (more on that below!). So dogs that have this genotype have varying shades in the middle of the spectrum. This dog will be or carry your lighter red, apricot, and darker creams.
i/i- The dog has two copies of the mutation causing the most lightening of pigment. This dog will be or carry light cream to white.
So let's say that black dog we were talking about comes back I/I. We now know that the dog has the ability to produce dark red dogs or dogs with dark red patterns. If that's your goal, you know this dog is a good candidate to produce it and when paired with another I/I dog.....you should get darker shades of red.
Keep in mind: This tests the shade the dog is born as. You still have to take into consideration progressive graying.
Want to get an embark test completed on your dog? Here’s the link for $64 off! Expires 12/17.
Ok so quick run down of incomplete dominant...
The best way to explain it is with a flower example. I know, you‘re being transported right back to high school biology. A red (homozygous dominant) flower is bred to a white (homozygous recessive) flower to give you PINK heterozygous offspring.
The offspring are a mix of the two parents.
The I Locus operates much the same way.
