Proving Dominant Traits

[reptileexperts]

So this is going to be possibly a beaten topic in other areas, but I did not see any imediate information on this available, so I thought I'd poke a dangerous bear and see what everyone thinks on this matter.

We tend to understate certain examples of dominant traits and need to better classify what we know and understand as dominant and how it truly relates back in the genetic community.

The Basics:

If we look at a Simple Dominance outcome you can say that the spider gene may look something like Xx and normal would of course be xx. Now, having that X makes it show the trait, spider. When we do a simple cross between a spider and a normal we would get the genetic ratios of half Xx and half xx. This is fine and dandy, and is where most people are fine with the concept.

The story of two hets:

Most of you should understand the concept of Het vs Homozygous, and when we refer to simple dominance we know that Hets and Homo individuals should be a represenative of this trait, whatever we may be dealing with, for my example, spider. So in order for us to consider spider dominant and not co-dominant, we need to do a cross between 2 adults that are both spider, this will theoretically be crossing Xx and Xx (again considering this was a first generation production for each, and again assuming simple dominance). Here's what the genetic wizard says about that . . .


Now, if we look at the combos of genes we would be getting a little bit different story, it would look more like 25% Normal, 25% Homozygous (XX), and 50% Het (Xy).

The truth and point:

So we've now broken it down pretty plain and simple, but I challenge you now to cross back EVERY spider produced by that previous clutch and cross it with a normal. In theory, at least 25% should be the Homozyous form, so when you find that individual, it will only be able to pass on an X rather than an x, thus continuing the spider gene.

The problem is, you won't be able to prove it, and the reason is simply that MANY of the morphs we associate as dominant, are actually co-dominant with Homozygous lethality in its super form.

Many people that seek out communities like this one, need to be properly educated about genetics if they want to pursue makin morphs. We also need to be careful about how we deem morphs when considering them for dominant vs co-dominant. For it to truly be dominant, you would still be able to get a super form, though it may not phenotypically be different than the het form, it would genotypically be vastly differnet and thus proveable. Think of a Blue-eyed Lucy (say lesser x lesser). If you breed that beautiful snake to a normal, you will get 100% Lesser offspring because Lucy can only pass on 1 gene. Co-dominant in its true nature usually works with genes. We can consider Lesser Co-dominant, because its super form is controlled by different alleles at the same Loci. However, things like Cinamon need NOT be referred to as Co-dominant, because our knowledge only demonstrates one known allele that can produce a super form, but at the same time we can't just refer to it as dominant because the super form is a different phenotype than it is in its heterozygous form!

Hopefully this doesn't confuse anybody, but perhaps encourages a beter look into this interesting subject. There are MANY factors at play when we mess with genetics and mutations, why do you think that Super Cinny are so prone to kinking? We're not just messing with the color of a snake, but we're also messing with its genetic make up that may very well be controlling something else. One last example would be Jaguar in Carpet pythons. We know that Jag is a form of Het Leacustic, when you produce a super form, it will die before it reaches its first shed, or early on in the stages of development due to poor lung development amoung other factors (Muton, 2011).

Cheers to those who read this fully and appreciate genetics for the science it really is!