Co-dominance and incomplete dominance

Hey guys,

I was looking over the herp abbreviations thread (maybe sticky) and it said that technically the codom BP morphs are incomplete dominant, not codom.

If this is true, why do people still call it codom? I was looking through a biology textbook, checking out the genetics unit. The definition and description of incomplete dominance seemed much more "fitting" to the "codom" traits I am aware of... really confusing.

So can someone tell me about the incomplete dominance and codominance in BPs?

Thanks,

***BUMP***

17 views and no one knows? Come on, folks.

I wrote that sticky, or at least the beginnings of it. Quite a few people have added definitions since my original list. I'll quote the co-dom definition here so people will know what we are talking about.

Quote:

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Originally Posted by kc261

co-dom - short for co-dominant, a genetic term meaning a trait which is the result of 2 equally dominant traits both being visible. A popular example is roan cattle which have a red gene and a white gene and have both red & white hairs. Curiously, most of the BP traits which are commonly referred to as co-dom are technically incomplete dominant traits, which is when 2 equally dominant traits blend together, such as pink flowers which have red gene and a white gene

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I also wrote the following (on a different forum), which probably does a better job of explaining how I feel about the subject:

Quote:

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It is easy to forget that words like dominant, recessive, codominant, and incomplete dominance are merely words made up by people. We should not be surprised when nature occasionally throws us something that does not perfectly fit any of these terms. I very much see the point that a mojave isn't really a blending of normal and super mojave/BEL in the same way that a pink flower is a blending of red and white. However, I believe it is closer to that than it is to the side by side expression it would have to have to be codominant. That would look more like a pied than a mojave.

So until biologists come up with another word to describe it, I will continue to believe that mojave and all of the other examples I am currently aware of, should be technically called incomplete dominance rather than codominance. However, as I said in my first post in this thread, I have no problem with the reptile community using the word codominant to include both codominant traits and incompletely dominant ones. They are just words after all, and imperfect ones at that.

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To answer your question more directly, I'm pretty sure it is a case of "because it has always been done that way". Probably the first, or at least one of the first people that discovered a "co-dominant" trait in the herp trade mistakenly called it co-dominant instead of incomplete dominant. Or maybe that one really was incomplete dominant. But most people don't remember their high school biology well enough to know the difference, so everyone started calling that type of trait co-dom.

It doesn't matter; we all know what we are talking about. Either one is a less than perfect description of what is going on. Either one tells that when a snake has a certain look, that means it carries a single gene, but if it carries a matched pair of that gene, it will have a different look. Neither one will tell us exactly what those looks will be, we either have to memorize it or at least know where to look it up. So it's close enough for me.

These are ball genetics..LOL...we have our own way of doing things. It does get hard at times at school with two different genetic meanings running threw your mind.

Codom is easier to say.
Don't underestimate the power of laziness!! lol
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Good question. Is has been on my mind for a while, but I never got to reading more about that.

Goed bezig :gj:

dont compare the way they teach genetics in your bio class and the way its done in the herp world. they are way different cuz breeders arent scientists. you gotta just leave biology text book genetics and herp genetics in two diff categories lol cuz as hard as you try they are not gonna match up right. im a bio major and argued with my profs. in the past and what i say here is what ive learned

In reality, a lot of people really dont understand the proper terminology. Even folks who have been breeding for years! I've had quite a few discussions on this board about terminology, and it ends up just confusing newbies more than anything.

I think a lot comes from our use of the word "super" to denote a codom animal as being homozygous.

And a lot of people dont understand that there is such a thing as a heterozygous pastel, sometimes they will get VERY passionate about it, and tell you that pastels can never be hets! They are confusing the word "het" as ONLY pertaining to a recessive gene, when het simply means the animal carries one copy of the gene, rather than two (which would make the animal homozygous).

And as for the term co-dom and incomplete dom, that is a whole nother ball park. I prefer to just go with codom, its easier than trying to figure which morph is this or that, and getting others to go along with that term.

Technically the wording may not be correct but its what is used.

Co-Dom=Homozygous animals are visibly different then hets and hets are visibly different than normals. I'd say it would be better off being called just a het or an incomplete dominant. Yes there are het pastels...they are regular pastels while the super pastel is a full pastel. If they were not hets then they wouldn't produce normals when bred to a normal. IMO it is called "co-dom" since you can combine 2 of the same dominant trait to get a visibly different animal.

Dom=Homozygous and het individuals look the same and you can only figure out the homozygous individuals by breeding. For example a het spider and homo spider look exactly alike but the homozygous spider will produce ALL spiders when bred to a normal while the het will only do half. You'd have to do a spiderxspider breeding and then hold back the 66% homozygous spider males to see which ones proved out when bred to a female. 100% spiders/pins etc... out of a normal would be pretty nice... IMO it is called "dominant" since there is only one visible trait for the gene.

So how would you tell if the heterozygous white\\red flower was really pink or just individual white and red dots so small and close together that it just looks pink?

I'm not so sure we can really tell which is right (co-dominant or incomplete dominant) for ball python morphs.