Reptile & Amphibian Forums

what can i read to learn about boa genetics. i want something really thorough, what to pair with what etc.
thanks

No such animal, as far as I know.

If you've had a good grounding in Mendelian genetics, then several would be useful. I like the morph page at http://www.reptimania.co.uk/boamorphs.htm, and there is good stuff at www.salmonboa.com and others.

If you have not had a good grounding in genetics, then do NOT try to learn it off the web. The genetics web pages I've seen run from fair to dreadful. Buy a text. Schaum's Introduction to Genetics, by Elrod and Standfield, costs less than US $10 for the latest edition (paperback) in good used condition. I like its problem-solving approach.

Good luck.

Paul Hollander

Paul, I learned genetics from six long months of web searches and many hours of difficult study. Are you saying what I have learned from these web tutorials was a waste of time and is wrong and I should go buy a book?

I think more so he is saying that it is more difficut. For someone who has no background at all in genetics, they may not be able to distinguish websites that are incorrect.

boagenetics.com is a fairly good site.
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- Jason F.

unlearn that which you learn incorrectly.

I know I had that problem and see it quite often with the Salmon/Hypo gene. I learned it as a "codominant morph" when it really is "Dominant morph". I still hear it called codominant all the time.
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Thanks,

Dave Colling

www.rainbows-r-us-reptiles.com

0.1 Wife (WC)
0.2 kids (CBB, selectively bred from good stock)

LOL, to many snakes to list, last count:
11.24 BRB
10.16 BCI
And those are only the breeders

lots.lots.lots feeder mice and rats

so, the hypo/salmon gene is just "dominant"!? If it was a simple dominant then an animal would either be hypo/salmon, or not. And it would either pass it on, or not. There would be no such thing as a "super salmon" with extra markers (more reduced pattern) than a regular salmon. An animal that is hypo/salmon WILL show it. Cannot hide. that makes it appear to be a "dominant" trait. But in reality, it is more like a co-dominant... Genetic inheritance of co-dominant genes works in essentially the same manner as genetic inheritance in simple recessive genes, except for the fact that heterozygous animals are visibly different than normals. These visible "hets" can be bred together to produce an even more extreme variation of the mutation, often called a "Super." The "Super" is a dominant form of a co-dominant gene, and can be bred to a normal animal to produce entire clutches of the visible het, or co-dominant form. Examples of co-dominant traits are arabesque, hypomelanistic, salmon, jungle, motley, and pastel.

Exactly my point, my following discussion is Phenotype only and the genes that go into them.

Co-dominant is where there are three visibly distinguishable phenotypes AA Aa and aa where A is a the dominant gene and a is the recessive gene. In Motley for example:

MM, two dominant Motley genes = purple patternless
Mm, one each dominant motley and normal gene = Motley
mm, two normal genes = normal

Dominant is where there are only two fully distinguishable phenotypes. NN and Nn are one phenotype while nn is the second.
In Salmon/Hypo for example

SS, two salmon genes = Salmon (while there are some markers that help pick out some of these, it is not 100% reliable as in Motley)
Ss, one each Salmon and normal gene = Salmon Many look just like the homozygous animals
ss, two normal genes = normal

Similar results for recessive traits Except, the phenotypes are switched since the Normal gene is dominant over the morph gene.

For example Albino,
AA, two normal genes (note they are capitilized since they are dominant) = normal
Aa, one each normal and albino gene = normal
aa, two albino genes = albino

The bottom line why Salmon is currently classified as Dominant is the Heterozygous animals cannot be 100% visually identified from the Homozygous ones. Yes, you can pick out some with a very high probability but you cannot for example take an entire litter of 50/50 het/homozygous animals and divide it into two distinct het and homozygous groups. That's why you see probable super, and possible super. Those that have the "look" little to no black around the tail blotches are probables, the rest are possibles. Maybe even those that really don't look it at all are marketed as salmons.

Super salmon is a slang term to describe a homozygous salmon. so a "super" salmon would pass the trait on to ALL of it's offspring.

>>so, the hypo/salmon gene is just "dominant"!? If it was a simple dominant then an animal would either be hypo/salmon, or not. And it would either pass it on, or not. There would be no such thing as a "super salmon" with extra markers (more reduced pattern) than a regular salmon. An animal that is hypo/salmon WILL show it. Cannot hide. that makes it appear to be a "dominant" trait. But in reality, it is more like a co-dominant... Genetic inheritance of co-dominant genes works in essentially the same manner as genetic inheritance in simple recessive genes, except for the fact that heterozygous animals are visibly different than normals. These visible "hets" can be bred together to produce an even more extreme variation of the mutation, often called a "Super." The "Super" is a dominant form of a co-dominant gene, and can be bred to a normal animal to produce entire clutches of the visible het, or co-dominant form. Examples of co-dominant traits are arabesque, hypomelanistic, salmon, jungle, motley, and pastel.
-----
Thanks,

Dave Colling

www.rainbows-r-us-reptiles.com

0.1 Wife (WC)
0.2 kids (CBB, selectively bred from good stock)

LOL, to many snakes to list, last count:
11.24 BRB
10.16 BCI
And those are only the breeders

lots.lots.lots feeder mice and rats

>so, the hypo/salmon gene is just "dominant"!? If it was a simple dominant then an animal would either be hypo/salmon, or not. And it would either pass it on, or not. There would be no such thing as a "super salmon" with extra markers (more reduced pattern) than a regular salmon.

The problem is that while many salmons with a pair of salmon mutant genes have the extra markers, many do not. This sort of thing is called "variable expressivity" and shows up every so often. So the question becomes, where do you draw the line? In my opinion, if at least 95% of the salmons with one salmon gene can be distinguished from those with two salmon genes, then salmon would best be classed as a codominant mutant gene. People on these forums say that nobody can do anywhere close to that. So I think that "dominant" is a better classification than "codominant" for this mutant gene. It is certainly not a recessive mutant gene.

>(much snipped) The "Super" is a dominant form of a co-dominant gene, and can be bred to a normal animal to produce entire clutches of the visible het, or co-dominant form.

This is the sort of vocabulary fostered on many herper web sites. Which is why I label them "dreadful" and recommend learning genetics from a text.

"Super" is herper slang unknown in standard genetics. A "super" is homozygous for a codominant gene. Or sometimes for a dominant gene. Some genes are codominants and some are dominants, but there is no such thing as a snake that is either the "dominant form" or the "co-dominant form". A snake that has a salmon mutant gene paired with a normal gene is heterozygous for salmon, a dominant mutant gene. A snake that has a pair of salmon mutant genes is homozygous for salmon, a dominant mutant gene. All the babies from a homozygous salmon x normal mating are heterozygous salmons and show the salmon phenotype.

Paul Hollander

just as i think im starting to understand i get completely confused again. lol man this stuff is confusing

i read boa genetics now i have a couple of questions to help me understand....
1. # Super Sunglow Homozygous Albino / Homozygous Hypomelanistic
is this a snake that is visually albino het for hypo crossed with a snake that is visually hypo het for albino??

2. are all salmons dominant???

3. if so then if you cross a salmon het for albino with an albino would you get salmon sunglows??? and if so what would the percentages be.

thank you everyone for your help

>i read boa genetics now i have a couple of questions to help me understand....
1. # Super Sunglow Homozygous Albino / Homozygous Hypomelanistic
is this a snake that is visually albino het for hypo crossed with a snake that is visually hypo het for albino??

An x is usually the symbol for a mating rather than a /.

Super Sunglow Homozygous Albino. To me, super sunglow is equivalent to homozygous salmon (AKA hypo) homozygous albino. So super sunglow homozygous albino would be equivalent to homozygous salmon homozygous albino homozygous albino. A second "homozygous albino" is unnecessary. This snake would have a pair of salmon mutant genes and a pair of albino mutant genes. It would show the salmon appearance, possibly the extreme form called "super salmon". It would also show the albino visual appearance.

Homozygous Hypomelanistic. This snake would have a pair of salmon mutant genes. It would show the salmon appearance, possibly the extreme form called "super salmon". I don't see any evidence that this is heterozygous albino in the listing.

A sunglow would be visually albino het for salmon (hypo). A snake that is visually hypo het for albino is probably a heterozygous salmon heterozygous albino, what the trade calls double het for sunglow.

>2. are all salmons dominant???

I'm not sure what this question means. But here is my answer to what I think it means.

All salmon boa constrictors have at least one copy of the same salmon mutant gene. The salmon mutant gene is dominant to the normal gene. The number of salmon mutant genes in a gene pair has nothing to do with whether or not salmon is a dominant mutant gene.

>3. if so then if you cross a salmon het for albino with an albino would you get salmon sunglows??? and if so what would the percentages be.

A sunglow is a salmon that is also albino. Seems to me that "salmon sunglow" is redundant.

Heterozygous salmon heterozygous albino (AKA DH sunglow) x albino -->
1/4 Heterozygous salmon heterozygous albino (AKA DH sunglow)
1/4 Heterozygous salmon albino = sunglow
1/4 heterozygous albino (looks normal)
1/4 albino

Hope this helps.

Paul Hollander

Hey, it's not that difficult. But a screwed up vocabulary screws up everyone. Start off with this:

Homozygous = two copies of the same gene in a gene pair. Examples: AA, aa.

Heterozygous = two different genes in a gene pair. Example: Aa.

Recessive mutant gene = Shows its effect only when homozygous. Symbolized with a lower case letter and fits the following pattern:
AA = homozygous normal, looks normal.
Aa = heterozygous because has a mutant gene paired with a normal gene, looks like an AA individual.
aa = homozygous mutant gene, shows the mutant appearance.

Dominant mutant gene = Shows its effect when either heterozygous or homozygous. Symbolized with an upper case letter and fits the following pattern, which is the mirror image of a recessive mutant gene:
AA = homozygous mutant gene, shows the mutant appearance.
Aa = heterozygous because has a mutant gene paired with a normal gene, looks like an AA individual.
aa = homozygous normal, looks normal.

Codominant mutant gene = Shows a different effect when heterozygous than when homozygous. Symbolized with an upper case letter and fits the following pattern:
AA = homozygous mutant gene, shows the full mutant appearance.
Aa = heterozygous because has a mutant gene paired with a normal gene, does not have the appearance of either an AA or an aa individual.
aa = homozygous normal, looks normal.

The codominant symbolism used here stinks. This forum won't show the plus sign, which is the standard symbol for a wild type or normal gene.

Paul Hollander

i thought that salmon was a dominant form of hypomelanism, and i saw something called a salmon sunglow that was quite different from a normal sunglow. thanks for your help i think im starting to understand.

I believe Salmon started out as a specific line of hypo but was used so much that it became synonomous with Hypo. Like Aspirin and Zerox.

>>i thought that salmon was a dominant form of hypomelanism, and i saw something called a salmon sunglow that was quite different from a normal sunglow. thanks for your help i think im starting to understand.
-----
Thanks,

Dave Colling

www.rainbows-r-us-reptiles.com

0.1 Wife (WC)
0.2 kids (CBB, selectively bred from good stock)

LOL, to many snakes to list, last count:
11.24 BRB
10.16 BCI
And those are only the breeders

lots.lots.lots feeder mice and rats

While often called hypo, salmon is the official name of one particular dominant mutant gene in the boa constrictor. There are other hypos that are not produced by the salmon mutant gene.

Paul Hollander

okay thats what i thought

I don't think I agree with that. What proof do you have that the Salmon gene is different than any other hypo gene?

I believe what Paul is saying is that there are other hypo genes besides just the Salmon/orange tail/hypo dominant form. Such as the Boawoman hypos, VPI "T plus" and Nic "T plus."
The T plus boas are really just another form of hypo.
Boas that are selectively bred for reduced black pigment such as pastels or boas which inherit hypomelanism in a polygenic manner like Hog island's could also be considered hypomelanistic.

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