Reptile & Amphibian Forums

I would like to address more fully what I consider to be an over-use of the term co-dominant. Please bear with me if I make some technical errors here, my biology degree was earned very many moons ago, but that's not the main reason I don't remember much from that period. (It was, after all, the late seventies. ) Okay, here's my point: Co-dominant should never have been used to describe the Salmon/Hypo trait. In scientific method, a thing called "Occam's razor" is usually used to help select a hypothesis. Simply stated, Occam's razor says that of two competing theories or explanations, all other things being equal, the simpler one is to be preferred. So if from the intial breedings of the hypo gene, if either co-dominant or simple dominant would describe the results, then simple dominant should have been chosen. (Theoretically, it should be clear from one breeding, but in the case of hypomelanism there are many other influences, such as naturally occurring "paleness" etc., which can mask the results, so several generations were required to clearly show the genetics: simple dominance.) In fact, unless there has been a radical change in the field of genetics since I went to school (which may well be the case), as I recall co-dominance is actually pretty rare, if it is being used in the sense of Mendelian genetics (XX shows the trait more than Xx). My point is that often a trait is governed by multiple alleles or variably expressive genes or God knows what. If a tall person mates a short person and the offspring has medium height, this is not the result of co-dominance. The closest thing I've seen to co-dominance in snakes is Tiger/ Super Tiger retics. I haven't followed the breedings very closely, but I question if even here the term co-dominant is appropriate. If the trait could be described as well by multiple alleles, wouldn't that be a simpler explanation? Maybe my confusion here is because I don't understand what people are referring to as co-dominant. If by co-dominant they mean Xxxx and XxXx is tiger, whereas XXxx, XXXx, or XXXX is Super tiger, then that would make sense. But again, if this is the case multiple alleles is a better description. My main concern here is that I see the term co-dominant thrown around a lot, as though the genetics are understood, when in fact the trait may be governed by something completely different.

And,I'm really glad someone besides myself expressed the idea! *lol* My opinion stems back to watching the whole thing unfold,and,I believe that initially the "co-dominant" label was chosen as a sort of "fail safe"...presenting something new to a group of your peers,and,for that matter,public consumption,is not without a large degree of cautious skepticism,and,doubt...assuming,(based on what we know now.)that the founding animals were hets,it seemed from the first few breedings,that the term best described what was seen as evidence...the popular thought at the time being,(I think) if it was truely dominant,ALL of the subsequent offspring would express the trait,which was not the case,only roughly half did,the term "incomplete dominance" was kicked around,however,I believe that may be the term that you mentioned in your post,which is sometimes used to describe situations where there are degrees of expressive variance,(Paul,or,Ron,feel free to kick me if I'm wrong on that part! )...anyway, durring these early breedings is where we also got WAAAAY off course with the whole filial connotation thing; F1,F2,etc...and,we still have very successful breeders refering to F2 this,or,that,thinking that breeding two Salmon animals from completely different sources means the offspring are F2...they are not,and,I've gotten to the point,where I have to completely ingore these claims,and,simply ask,"were the parents siblings?"...the entire thing seems to be perpetuated by a lack of basic understanding in the significance of initially keeping track of related,possible gene carriers for the trait that is being explored,or,researched...the primary stumbling block in accepting Salmon/Orange-tails as a dominant trait,lies in confusing the transmissive nature of a given individual with the classification of the trait itself...there's no need to say that a "super" is "dominant",and,an "intermediate",(or het.) is "co-dominant"we should already know that...we are talking about two individuals expressing the SAME TRAIT,the exact same way we refer to albinos,and,hets...what is the trait? amelanism...what is the expressive status? het. or,homozygous,the only real difference is that with dominant forms,the hets express the trait,and,recessives don't...the transmissive result when bred,are the same.

Yes, I'm an idiot. I didn't understand it, but I love that post!(That's my best Beavis and Butthead impression.)

Miller Reptiles

No are we all just trying to show off our intellect for all the snake chics out there or are you people really this damn smart? I understand that some science is needed for the breeding, care and maintenance of our animals, but this is just getting silly. Your post reads more like my 17 year olds algebra problems then it does a breeding or care question. But seeing you brought up the example of the tall man and short woman (or was it a tall woman and short man?....) this is something that I can relate to.
This example is a completely wrong analogy. Your example indicates that the two genes fused to combine and result in a medium sized child. This is not the case in the salmon line of hypos. The co-dominate term was/is used to explain that with each breeding of a normal boa to a first generation hypo you will get an equal amount of offspring that show the traits of either parent. They won’t combine to blend and make just a little bit litter boas, half will be salmon and half will not be (statistically). Whether or not that is the proper way to describe it to a biology professor or a genealogist (is that even a word?) is not the point, it worked to explain it to the herpers of the world who were going to be using the trait in future breedings.
If you had told me that the trait was “simple dominant” then I would have expected it to be dominant through the entire clutch instead of sharing the dominance with the normal coloring trait. As far as how many alles it took to make the trait, it means nothing to me because I am not sure of what the heck an alle is or why it is making things inside my snakes. Thanks for trying to explain it to me but I am just to old to learn new tricks LOL!
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Jim Hopkins "Hoppy"
Hopkins Holesale Herps
Hopfam1@aol.com