its rare and expensive and its purpose is very clear, its to make highways.

i guess the people that first get them just pair them to ivory, and ivory combos, making sure that every hatchling that gets the gravel gene will be a highway. and then you can continue with pairings of highway to ivory.


about "het highway", well, even if the genes are codominant, a certain trait or phenotype can still be recessive. blue eye leucistic, black eye leucistic and ivory are all recessive traits, while the genes that produce them are codominant.