Genetics be it kitties or doggies is fascinating. I have two white sable dogs and 1 silver sable dog. It’s amazing what you can come up with. They all have the same father who is a pure white. The girls mother is a white sable and the boy’s mother is a light gray sable. The father and mother of the girls produced an entire white sable litter which is the only one ever produced in this breed with a white father and white sable mother. They said it couldn’t be done. I think it was because the father had a lot of whites in his background and the mother had a lot of whites in her background. Probably a double recessive white gene there.
However, the father and the gray sable produced a litter of no whites and 4 silver sables.
Genetics is so cool; and you can predict what the pups might be; but then you get that occasional odd one that’s been hiding. LOL like the chocolate in your blue’s history.
So, it’s kind of a crap shoot.
The blue can be to some extent an imperfect recessive or partially expressed recessive -- still showing blue but having some of the qualities of the seal/chocolate color. The dilute factor is even more difficult to deal with.
Of course it's a crap shoot -- that's what makes it so much fun! My younger dog's breeder had to laugh at the mathematical inclinations of Ruby's mom -- she was a Yellow bred to a yellow-factored Black, which should mean 50 percent yellow and 50 percent yellow-factored Black. She had TWO black males, TWO black females, TWO yellow males, and TWO yellow females. She really likes symmetry in her litters . . .
That’s almost as good as DNA. LOL