Is it Codominance or Incomlete Dominance?

I am having a hard time with the whole Co Dominance or Incomplete Dominance?

Here is where I am confused. Take an Ivory Ball Python for Example.


Parents => Offspring

Ivory X Normal => YB YB YB YB
YB X YB => Ivory YB YB Normal
YB X Ivory => YB YB Ivory Ivory

Now look at Snap Dragon Flowers with Incomplete Dominance

Parents => Offspring

White Flower X Red Flower => Pink Pink Pink Pink
Pink Flower X Pink Flower => White Pink Pink Red
Pink Flower X White Flower => White White Pink Pink

It seems to me that most of the Co-dominate Balls are actually Incomplete Dominate. Am I wrong on this? What are your thoughts?

Joe Ellis

To the best of my knowledge, Co-Dominance and Incomplete Dominance are two terms for the same thing :confused: I've even asked my science/bio teacher and she said it's different names for the same thing.

the real correct term is incomplete dominance, but co-dominant is the same thing, just a different/slang term

That's the way I've always understood it, yeah.

My understanding of the terms is that incomplete dominance occurs when both alleles are partially expressed, and so you get a kind of "blended" expression of each -- like the pink snapdragons -- while co-dominant alleles are both expressed equally.

I think of pastels when I think of incomplete dominant. If you figure a "pure" pastel (homozygous pastel, AKA "super") is a bright yellow snake with lots of blushing and shades of purple, and a pure normal ball python (homozygous wild-type) is a black and brown snake, the heterozygous pastel is kind of a mix between the two.

The best example I know of true co-dominant is in human blood typing. Heterozygous AO, and homozygous AA, are the same -- blood type A (with only the A antigen expressed). Same for heterozygous BO and BB -- only the B is expressed. Heterozygous AB, on the other hand, is blood type AB -- both are expressed.

I don't know of any examples of (what we suspect would be) true co-dominance in python morphs ... Anybody?

The other thing that baffles me is what's going on with the BEL complex stuff ... The heterozygous form of a mojave, for example, does not in any way seem to be a "blend" of the homozygous mojave and the homozygous wild-type. :confused: Maybe it's my lack of understanding, or maybe it's just that we oversimplify Mendelian genetics a bit too much ...

But yeah, as BAMreptiles says, "codom" is generally the accepted slang term -- it's a bit easier to say/type than "incomplete dominant" :rolleyes:

If you where in a genetics class, the correct term would be incomplete dominance.

Co-dominance and incomplete dominance are two separate deals all together, they are not the same thing. The Ball python herping world has a loose understanding of genetics, it is not 100% accurate.

Incomplete dominance is like such; Yellow + Blue = Green. When 2 alleles combine together and are represented in a mixed appearance.

Co-dominance is like; Brown + Black = brown and black striped. When 2 alleles com together and are both visible at the same time.

well according to my college level bio classes, they are the same thing, just different slangs basically