Recently I had a customer ask me about the genetics of a Spider Ball Python. He was told they were a Co-Dominate vs Dominate. And even though I generally feel that most reptile owners know a little bit about genetics and would be able to answer this question themselves, I suddenly remembered that we all have to start out some where with our adventures with reptiles and that there are no dumb questions ever ask. So I do realize that 90-95% of you in this forum know the answer to this question, I have posted the answer for the other 10-5% that may not know the answer.
The original Spider was a imported Ball python, N.E.R.D ( Kevin McCurley) produced the first babies in 1999. They were proven to be a Dominate trait unlike the Pastels that are Co Dominate which produces a Super when two are breed together(Super Pastel-Dominate). A Super(Dominate) breed to a normal Ball Python will produce all visible Heterozygous(Co Dominate) animals. Co Dominate genes are generally the same as a simple recessive genes except that Heterozygous animals of Co-Dominate breeding to a normal ball python are visible(Phenotype) different than recessive ball pythons(Homozygous) breed to a normals ball python which would produce all normal looking babies(Phenotype), but have the genetic make up(Genotype) of that recessive ball python. I hope this answers your question about the Spider.