|Cornsnake Morph Guide ®||Pattern Formation||Charles Pritzel|
The borders are created by a group of cells surrounding the original group. This also grows as the saddles expand.
The fourth group, which forms the belly checkers, does not appear to start with red, but rather expands to fill the scales with black, from the outside "flat edge" to the centerline, and from the front to back edges of the scales.
A large number of genes are responsible for controlling the destiny of these pigment cells. As such, a large number of different mutations can modify the way these cells migrate, whether they live or die, the direction and/or pace of their migration, and the direction and/or pace of their expansion. Following are some examples of patterns and how they might be viewed using the migration model.
The well-known standard hypomelanism, which has long been considered a "color morph," may fit this model as a pattern gene. It appears that the border areas on snakes homozygous for hypo are often significantly thinned, even when melanin is not being produced. This is especially apparent when comparing the borders on ultramelsversus hypos. (Ultramels appear to have normal-width border areas.) It is possible that hypomelanism actually slows or otherwise hampers the migration or division rate of "border cells" and "checker cells" thus causing the pattern to have smaller border areas. This could also cause the belly checkers on hypos to be faded and/or not completely reach the center of the belly.
A new mutation, known as cinder, appears to affect the number of saddles that appear along the length of a snake's body, increasing saddle counts by approximately 25%. This could be caused as the groups initially subdivide, by increasing the frequency of these divisions. Similar mutations might be found which do the opposite, and lower the snake's saddle count.