I think it would be interesting if someone could piece together what Applejack's parents family. We already know genetics work in a fictional world filled with talking horses, so we can get some idea of what they would look like. One thing I noticed is that the offspring tend to carry most of their traits from one of their parents instead of being balanced out in the real world.
genetics lesson go
For example, Twilight's and Shining's parents.
It is clear that Twilight gets most of her genetics from her father like his coat and mane. She gets her mane style from her mother (I wouldn't count hair styles as a trait but just roll with it)
Shining appears to get most his traits from his mother and no notable traits from his father. Eye color, mane, and coat color all seem to tie to the mother.
And another example
It seems both Inkie Pie and Blinkie Pie both share similar coat colors from their mother. Except for Blinkie Pie for getting her eye color from her father.
I'm not sure where Pinkie Pie got her coat and mane color, probably from some pony further up the tree we are not aware of. However she does have her eye color from her mother.
So Applejack's parents will be difficult because we have 3 different ponies with 3 different coat colors. Eye color will be easy, since all 3 seem to carry the exact same color.
I'm pretty sure there is some pattern in genetics in here I'm too lazy to look into. Hopefully someone did their homework in 7th grade science class and is able to find dominant genes in colorful talking cartoon horses.
Just an interesting thought.
