As I recall from Michael McEachern's corn snake color and pattern booklet, somebody started with particularly red North Florida stock and then selected them for the reddest he could get over a number of generations. The result was the blood red line. It has been outcrossed extensively since, partly to eliminate the reproductive problems in the original stock and partly to combine with other mutants
The red color is apparantly from selection. I am inclined to think that the bleedover of orange/red on the belly also resulted from the extreme amount of red pigment present. I've seen considerable amounts of orange/red pigment on the bellies of Okeetee corns.
The blood red pattern mutant's full blown phenotype seems to involve killing the belly checkering and diffusing the dorsal and lateral blotching so that the blotches do not stand out from the ground color.
McEachern called the blood red pattern mutant a recessive mutant gene. But past posts on this forum indicate that when heterozygous, the blood red pattern mutant can produce a noncheckered or partially checkered belly while having little or no effect of the lateral and dorsal blotches. I do not know how reliable the effect is for identifying the heterozygotes from the normals. I think more work needs to be done with the mutant to check out its range of effects.
Paul Hollander
