Tested Pony: Misty's Hurricane Izzy

The last pony in my tested ponies series is my own! If you have a color tested pony and would like me to feature them just message me with their test results and some pictures.
My pony Misty's Hurricane Izzy is a Misty descendant and a daughter of chestnut tobiano Misty II's Henry. Izzy's solid black dam Stars Black Velvet was born on Assateague in 1994. Her test results weren't a surprise to me because what I know about her family but there's still things to discuss and learn from!

Izzy is a bay and she tested as A/a, or has one copy of Agouti. Agouti restricts black to the points. Because her dam is black and can't have agouti, that means it came from her chestnut sire. Henry's sire is a bay so that's likely where it came down from.
She tested as E/e which means she has one copy of extension from her black dam. The combo of extension and agouti are what made her a bay. The small e means she has a copy of recessive chestnut. Since her sire is a chestnut he passed one copy on to her. Chestnuts always pass one copy of chestnut on to their offspring.
She doesn't have a dorsal stripe or any other primitive markings and her test reflects that as nd2/nd2.

Izzy is obviously a pinto and she tested as TO/n. She only has one copy of tobiano because only her sire is a tobiano. She has a good bit of roaning. While her type of roaning is more common on tobianos with two copies of tobiano, she has it with only having one. In my opinion she has a lot of white and a rather large star to be tobiano only. If she has another white/pinto pattern then it's one that hasn't been found yet. I've run every white test available on the market and she doesn't have any of them.

She had three foals with three different stallions, here's what she had:
Chestnut tobiano splashed white. Sired by a chestnut tobiano splashed white.
Black tobiano. Sired by a brown tobiano.
Bay tobiano (a lookalike!). Sired by a homozygous black tobiano.