I am beginning to lean towards it being a gene. My reasons for this conclusion is that of the 6 eggs laid (5 good eggs and 1 slug) 2, maybe 3 of the hatchlings seem to be exhibiting an influence from their mother's appearance, which is the odds you would expect to see for an incomplete dominate gene. If it was more of a line bred trait, I would expect all of the hatchlings to show an influence (not to the same degree of course, but some darknes and pattern distortion in all of the hatchlings). Also, the amount of influence shown on the pattern of the male Jigsaw 2 and the male Pastave seems to be more drastic than I would expect from a line bred trait. Of course, future breeding is the only way to know more with any degree of certianty.