Can a codom/incdom be a "het"? Are there recessives at all or are all genes codoms?
Let me clarify things a bit for you guys. When we are talking about phenotypes/visual appearances in snake genetics, we are talking about mutations on the snakes' genes or probably more specifically, alleles. Genes are what make up chromosomes. Humans have tens of thousands of genes on our 23 chromosomes (some animals and even plants have more). They are a set of instructions on how to build the organism.
Since most animals get genetic information from each parent, most animals have one allele from father and one allele from mother, together called a gene. If one of these two alleles are different, the gene is heterozygous. If the two alleles are the same, the gene is homozygous. Recessive and codom/incdom are simply terminology. People get in a fuss over nothing but semantics, really. Both terms, recessive and codom/incdom, can be either heterozygous or homozygous. For example, a Pastel is heterozygous because it has one "Pastel" allele and one wild type allele. A het Albino is heterozygous because is has one "Albino" allele and one wild type allele. A super Pastel is homozygous because it has two "Pastel" alleles. Similarly, an Albino is homozygous because it has two "Albino" alleles.
Now, recessive is simply a term to describe a situation where the heterozygous gene (two different alleles- normal from one parent and morph from the other) DOES NOT express a mutated phenotype (visual expression) and appears the same as a wild type (normal). Codom/incdom is simply a term to describe a situation where the heterozygous gene (two different alleles- normal from one parent and morph from the other) DOES express a mutated phenotype (visual expression) and appears DIFFERENT than a wild type (normal).
People generally use an obvious and easy to distinguish gene (allele) such as a Pastel or Albino as an example here. Pastel is codom/incdom and Albino is recessive. Where some people disagree is, for example, the situation that arises in Piebalds. It is very well known that Pieds sometimes have what people call "markers" or clues that the supposed "Normal/Wild Type" appearing snake has one allele that is Pied, making the snake "het for Pied". Some people call these "tram lines" or track lines" or similar. Because some mutations that are historically and commonly considered recessive do often have less noticeable phenotypical variances (visual expressions), there are some people who believe that ALL mutations have "markers" or varying phenotypes (visual expressions). These people say "There are no recessives, only codoms/incdoms." because they think they can spot "markers" in every snake generally considered het recessive.
The problem is that "recessive" and codom/incdom" are just terms, not precisely defined definitions. If recessive was defined as "an allele with a phenotype having the appearance observably unidentifiable by a random group of 9 out of 10 people whom hold the the certification of "Masters in Python regius Identification", we would not have this problem that I am spending an hour of my day explaining! Since we do not have that definition, just take the terminology with a grain of salt. Maybe all recessive snakes have markers that we are just not trained to see, maybe not. I highly doubt it but if people want to think they can pick out het albinos from normals 99% of the time, let them think so. Maybe they're gifted or highly trained and see something we don't. Still, the populous doesn't see it and its just general terminology. Thanks!