Tested Pony: Assateague's Spirited Lady

This week's featured tested pony is Assateague's Spirited Lady from Hart’s Island Pony Ranch. As her name implies she was born on Assateague and is by the bay tobiano Ajax and out of chestnut tobiano Courtney's Island Dove. Both of her parents are still on Assateague. Lady is a seemingly plain solid bay but her genetics are very interesting!

Lady's basic makeup as a bay showed up as E/e and A/a. She has one copy of extension that gives her black pigment and one copy of agouti which restricts that black to the points. The small e means she carries recessive chestnut. Chestnut was inherited from her chestnut tobiano dam.

In the second photo you can see that she has a dorsal stripe. And in the third can see that she has leg striping. She's the best example of leg striping I've seen in Chincoteagues. Despite these she's not a dun. Her primitive markings are from a mutation called non-dun1. Lady tested as having two copies or nd1/nd1. She'll pass a copy of nd1 on to all her offspring so there's a high chance her foals will have some kind of primitive markings.

Now for the really interesting part. Lady the solid bay tested as having four white patterns! They are White 34, White 35, EDXW2, and EDXW3. She's the only Chincoteague to date that has been tested to have W34, one of two known to have W35, and of the first to be found to have Eden Whites. I'd eyed both of her parents as having something other than tobiano so that part wasn't a surprise. All four patterns have been discovered within the past 2 years so we don't know a whole lot about them and why a solid bay could have them. Perhaps some kind of white suppression keeping any of them from putting white markings on her. Or maybe they're white boosters that require a more visible pinto pattern in order for them to appear. Maybe more than one copy changes things. More research and time will tell!

Lady is expecting a 2025 foal and it will be bay, black, or chestnut. The sire Cyclone II is homozygous for tobiano so the foal is guaranteed to be a tobiano. I'm looking forward to seeing if Lady's unseen white patterns show up or affect the foal's tobiano!