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Trying to put together a Genetics 101 primer related to Boa morph genetics. Would appreciate any and all suggestions/corrections. Specifically in the description of the various morphs. Or any thing I left out. I'd like to make changes/corrections and save the doc for reposting when newbies such as mysef ask some of the basic genetics questions, maybe not even the whole primer, only the applicable sections?

Be kind....

Genetics 101:

Terms:

Mutant gene = any gene that is different from the corresponding normal gene. Not necessarily a visual mutation.

Het = heterozygous = having two different genes within a gene pair. Most commonly one normal and one mutant but could be two different mutant genes.

Hom = Homozygous = having both genes within a gene pair the same. Can be normal or mutant.

Super = slang term commonly used for Hom dominant mutant gene pair.

Trait = Physical appearance that it distinguishable from normal.

Recessive = Trait is only expressed when the gene pair is Hom for the specific mutant gene.

Dominant = Trait is expressed when the gene pair is Het or Hom for the specific mutant gene. Het and Hom specimens are not 100% distinguishable from each other. Note, in some Dominant traits some of the specimens can be visually identified as Het or Hom.

Codominant = Similar to Dominant except the Hom specimen will have a 100% distinguishable appearance from a Het specimen.

Double Het = has two gene pairs where one gene in each pair is normal and the second gene is a mutant gene. Ie double Het for snow would have a normal gene paired with an albino gene and a normal gene paired with an anerythristic gene.

Triple Het = same as double Het except applies to three gene pairs.

Some identified visual traits in boas:

Albino - Recessive - a lack of black pigmentation

Anerythristic - Recessive - a lack of red pigmentation

Stripe - Recessive - sections of dorsal patterns that are connected in a continuos stripe.

T-positive - Recessive - ..........

Hypo - Dominant - a reduction in the black pigmentation

Motley - Codominant - A pattern morph where .........

Jungle - Dominant - A Swedish line of boas that........

Arabesque - Dominant - a pattern morph where ........

Pastel - A line of boas selectively bred for less than normal black pigment, not related to a single gene pair.

Some named multiple gene pair combinations:

Snow - Albino and Anerythristic
Ghost - Anerythristic and Hypo
Sunglow - Albino and Hypo
Moonglow - Albino, Anerythristic and Hypo
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Thanks,

Dave "Rainbows-R-Us"

0.1 Wife (WC)
0.2 kids (CBB)
2.7 Brazilian Rainbow Boa (adult breeders)
2.5 Brazilian Rainbow Boa (sub-adult from 2004)
4.8 Brazilian Rainbow Boa (sub-adult from 2005)
2.1 Hypomelanistic BRB
0.1 Het for Hypomelanistic BRB
0.1 BCI "Elvira" normal from 1989
1.0 BCI albino / het-anery
0.1 BCI Hypo / het-albino
0.1 BCI Anery / het-albino
0.1 BCI Hypo (possible super)
1.0 BCI albino het stripe
1.0 BCI salmon hypo
0.1 BCI ghost

lots.lots.lots feeder mice and rats

Seems pretty sound to me except for a few things ...
- Usually homozygous is shortened to homo not hom
- Jungle is co-dominant not dominant

This is a list I have been working on maybe it will help you.

Color Mutations:
Albinistic – recessive – two strains: Khal and Sharp
Tyrosinase Positive Albinistic - recessive
Hypomelanistic – dominant
Anerythristic – recessive – two strains: type I and type II
Pastel – polygenic
Blood - recessive

Color Mutation Combinations:
Ghost – homozygous anerythristic heterozygous hypomelanistic
Super Ghost - homozygous anerythristic homozygous hypomelanistic
Snow – homozygous anerythristic homozygous albinistic
Sunglow – homozygous albinistic heterozygous hypomelanistic
Super Sunglow - homozygous albinistic heterozygous hypomelanistic
Bloody Salmon – homozygous blood heterozygous hypomelanistic

Locale Related Color Mutations:
Sunset – homozygous hypomelanistic having 50% Hog Island Boa blood
Slamontine – heterozygous hypomelanistic having 50% Argentine Boa blood

Pattern Mutations:
Arabesque – dominant?
Jungle – co-dominant
Motley – co-dominant
Stripe – recessive
Reverse Stripe – recessive?
Leopard – recessive?

note: '?' indicates mutations where genetic inheritance is not fully known.
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- Jason F.

Leopards are recessive.

It is Kahl not Khal.

And I would change Albinistic to Albino (T-plus) or Amelanistic (normal type).

Hope this helps.

Didnt catch the Kahl mistake thank you.
I was under the impression that there have been pattern changes in hetereozygous leopards. Although from what I understand it may have had something to do with the specific animals being bred. Has this trait been proven recessive and if so is it known what caused the pattern changes in the hets of that particular breeding?

Again, I appreciate the help.
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- Jason F.

saying that the Arabesque trait is also Dominant. The photos I saw of last years (?) Arab x Arab that Steve H. produced, did no show a big variance in the offspring....one could compare it's differences to the hypo & super hypo morphs......
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Chris & Alliey
www.bloodyleopard.com
E-mail Us

I can agree to some extenet. There was an obvious pattern difference (thinner saddles, some not connecting etc) between the possible supers and the regular hets.
I would relate the pattern difference with many hypo arabesques.
I agree that there is no extreme difference as in motleys for example, but being a pattern mutation, they are not identical.
Eventually after more breeding trials are done the inheritance will be determined. The pattern differences could just be due to something with that particular litter.
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- Jason F.

Could we maby also include some info on the square tails and the aztec morph. What about the pastels? Thanks

NP

do understand this correctly:

Kahl/Sharp albino should be called amelanistic

and

Tyrosinase positive should be the only albino?

Very much appreciate the help!!!!!!
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Thanks,

Dave "Rainbows-R-Us"

0.1 Wife (WC)
0.2 kids (CBB)
2.7 Brazilian Rainbow Boa (adult breeders)
2.5 Brazilian Rainbow Boa (sub-adult from 2004)
4.8 Brazilian Rainbow Boa (sub-adult from 2005)
2.1 Hypomelanistic BRB
0.1 Het for Hypomelanistic BRB
0.1 BCI "Elvira" normal from 1989
1.0 BCI albino / het-anery
0.1 BCI Hypo / het-albino
0.1 BCI Anery / het-albino
0.1 BCI Hypo (possible super)
1.0 BCI albino het stripe
1.0 BCI salmon hypo
0.1 BCI ghost

lots.lots.lots feeder mice and rats

Amelanistic / Albino (T negative) Sharp / Kahl strains
Caramel Albino (T positive) Colombian / Nicaraguan strains
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Chris & Alliey
www.bloodyleopard.com
E-mail Us

Getting there....

Caramel, not familiar with those at all, in the replies I've seen:

Caramel Albino (T positive) Colombian / Nicaraguan strains

Caramel Hypo (Boawoman Hypo)-recessive-a Hypomelanistic trait with similarities to Colombian T-plus Albinos and Pastels.

????? one or two entries
-----
Thanks,

Dave "Rainbows-R-Us"

0.1 Wife (WC)
0.2 kids (CBB)
2.7 Brazilian Rainbow Boa (adult breeders)
2.5 Brazilian Rainbow Boa (sub-adult from 2004)
4.8 Brazilian Rainbow Boa (sub-adult from 2005)
2.1 Hypomelanistic BRB
0.1 Het for Hypomelanistic BRB
0.1 BCI "Elvira" normal from 1989
1.0 BCI albino / het-anery
0.1 BCI Hypo / het-albino
0.1 BCI Anery / het-albino
0.1 BCI Hypo (possible super)
1.0 BCI albino het stripe
1.0 BCI salmon hypo
0.1 BCI ghost

lots.lots.lots feeder mice and rats

Mike Wietzman (Basically Boas) is working with the Boawoman Hypo and has given it the name Caramel, to distinguish it from other Hypos and cause less confusion. They are still Hypomelanistic, but look entirely different. For other people reading this, remember Hypomelanistic just means less black pigment. Pastels are also a type of Hypomelanistic.

Caramel has also been used for the T-Plus Albinos, particularly with the Colombian morph.
The T-Plus label is used enough that I would leave it as that.

It is confusing with two things being called Caramel. I do think Tracy and Mike use different spellings of it though.

Anyway, they are two different mutations.

A T-negative albino lacks black pigment because a defective tyrosinase enzyme prevents black pigment from forming. A T-positive albino lacks black pigment because a defect in an unknown enzyme (other than the tyrosinase enzyme) prevents black pigment from forming.

I asked Dave Barker several years ago whether any boas or pythons had actually been tested for tyrosinase activity. He said no, and I have not heard different since then.

There are four possibilities:
1. The Kahl strain of albino is T-negative, and the Sharp strain is T-positive.
2. The Kahl strain of albino is T-positive, and the Sharp strain is T-negative.
3. Both strains are T-positive.
4. Both strains are T-negative.

We do not know which possibility is correct. However, as far as I know, there is only one gene locus that produces the tyrosinase enzyme. As the Kahl and Sharp strains are not compatible, there is essentially no chance that both strains are T-neg.

In other words, calling both the Kahl and Sharp strains of albinos tyrosinase negative albinos is almost certainly incorrect.

The mutants that people call T-positive albinos have some black pigment. They could produce the observed effect because of a partially functional tyrosinase enzyme or because of a nonfunctional or partially functional enzyme that has not been identified yet. For what it's worth, Siamese cats are lighter than normal cats because Siamese cats have a partly functional tyrosinase enzyme.

I'd like to see the Kahl and Sharp albinos given unique names. I'd also like to see the two anerythristics, the two caramels, and the various "T-positive albinos" given unique names. This would eliminate a lot of confusion. Anyone who can persuade the boa breeders to do this would have my unbounded admiration.

Paul Hollander

Thanks Paul, Give me a big enough stick and I'll convince the boa breeders

How about this for now:

Color mutations in boas:

Albino/Amelanistic - Recessive - a lack of melanin (black pigmentation) Kahl and Sharp strains.

Anerythristic - Recessive - a lack of ______ (red pigmentation) two known strains (type I and type II)

Hypomelanistic - Hypo - Dominant - a reduction in the black pigmentation

Caramel Albino (Tyrosinase positive) : Recessive - Colombian and Nicaraguan strains

Caramel Hypo (Boawoman Hypo)-recessive-a Hypomelanistic trait with similarities to Colombian T-plus Albinos and Pastels.

Pastel - Polygenic - A line of boas selectively bred for less than normal black pigment, not related to a single gene pair.

Blood - Recessive - A Hypererythristic mutation.
-----
Thanks,

Dave "Rainbows-R-Us"

0.1 Wife (WC)
0.2 kids (CBB)
2.7 Brazilian Rainbow Boa (adult breeders)
2.5 Brazilian Rainbow Boa (sub-adult from 2004)
4.8 Brazilian Rainbow Boa (sub-adult from 2005)
2.1 Hypomelanistic BRB
0.1 Het for Hypomelanistic BRB
0.1 BCI "Elvira" normal from 1989
1.0 BCI albino / het-anery
0.1 BCI Hypo / het-albino
0.1 BCI Anery / het-albino
0.1 BCI Hypo (possible super)
1.0 BCI albino het stripe
1.0 BCI salmon hypo
0.1 BCI ghost

lots.lots.lots feeder mice and rats

>Color mutations in boas:
>
>Albino/Amelanistic - Recessive - a lack of melanin (black pigmentation) Kahl and Sharp strains.

Albino (AKA Amelanistic) - Two independent mutant genes; both recessive - a lack of melanin (black pigmentation). Kahl and Sharp strains.

>Anerythristic - Recessive - a lack of ______ (red pigmentation) two known strains (type I and type II)

Anerythristic - Two independent mutant genes; both recessive - a lack of red pigmentation. Two known strains (type I and type II)

>Hypomelanistic - Hypo - Dominant - a reduction in the black pigmentation

Salmon (AKA Hypo) - Dominant - a reduction in the black pigmentation and often some increase in the yellow pigmentation.

>Caramel Albino (Tyrosinase positive) : Recessive - Colombian and Nicaraguan strains

Caramel Albino (AKA Tyrosinase positive albino) - believed to be at least two independent mutant genes; all recessive - has less than the normal amount of black pigment. Colombian and Nicaraguan strains

>Caramel Hypo (Boawoman Hypo)-recessive-a Hypomelanistic trait with similarities to Colombian T-plus Albinos and Pastels.

Caramel Hypo (Boawoman Hypo) - recessive - has less than the normal amount of black pigment, similar to Colombian T-plus Albinos and Pastels.

>Pastel - Polygenic - A line of boas selectively bred for less than normal black pigment, not related to a single gene pair.

Pastel (AKA Hypo) - Polygenic - A line of boas selectively bred for less than normal black pigment; not caused by a single mutant gene.

>Blood - Recessive - A Hypererythristic mutation.

Sorry; I know zip about bloods.

Paul Hollander

np
-----
Thanks,

Dave "Rainbows-R-Us"

0.1 Wife (WC)
0.2 kids (CBB)
2.7 Brazilian Rainbow Boa (adult breeders)
2.5 Brazilian Rainbow Boa (sub-adult from 2004)
4.8 Brazilian Rainbow Boa (sub-adult from 2005)
2.1 Hypomelanistic BRB
0.1 Het for Hypomelanistic BRB
0.1 BCI "Elvira" normal from 1989
1.0 BCI albino / het-anery
0.1 BCI Hypo / het-albino
0.1 BCI Anery / het-albino
0.1 BCI Hypo (possible super)
1.0 BCI albino het stripe
1.0 BCI salmon hypo
0.1 BCI ghost

lots.lots.lots feeder mice and rats

First I would just like to say I admire you interest and understanding of genetics especially boa genetics. I am also one who does not care so much for the mutation names that do not describe the actual mutation.

While I agree with most of what you posted, I not so sure I agree that there is NO chance that the Kahl and Sharp strains of albino are not both T-negative. There is obviously the possibility, but couldnt they just be alterations in different amino acids that are used to make up the tyrosinase enzyme?
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- Jason F.

>While I agree with most of what you posted, I not so sure I agree that there is NO chance that the Kahl and Sharp strains of albino are not both T-negative. There is obviously the possibility, but couldnt they just be alterations in different amino acids that are used to make up the tyrosinase enzyme?

In black rat snakes, there are two forms of albino. Both have been tested for tyrosinase activity. One is tyrosinase positive and the other is tyrosinase negative. Crossing the two produces normal-looking babies.

As far as I know, crossing Kahl and Sharp strains produces normal-looking babies. Does the parallel continue -- one boa albino tyrosinase positive and the other tyrosinase negative? I think that is very likely because I was taught that one gene contains the entire genetic information for an enzyme. The only variant tyrosinases that I know of are produced by alleles of the same gene. And if the Kahl and Sharp mutants were alleles, crossing the snakes would not produce normal-looking babies.

I'd be delighted if someone actually tested both strains of boa albinos for tyrosinase activity. We can spin hypotheses from here to breakfast, but only testing will settle it.

Paul Hollander

I deffinately agree that testing would help with the whole understanding of boa genetics.

It does make sense to me that the information for an enzyme would be on the same gene. The way I am looking at it is that there are multiple amino acids required to make an enzyme and if one strain caused a disruption in one amino acid required and the other strain caused a disruption in another amino acid then they would not be compatable together. Additionally they would not need to have an alternative appearance when crossed because they were disrupting different amino acids from the same chromosome.

Again like you said these are just theories and we can make as many as we want but without any testing there will be no evidence to support either. I wonder how difficult it would be to get this testing done ... well it would be difficult for me as I do not own any type of albino.

Glad to have people on the boards concerned with untangling the genetics of these amazing animals.
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- Jason F.

What you'd get would be a slightly variant form of the original gene. In other words, this variant form would be an allele of the form already present. Two different alleles still make a gene pair (in herper parlance, are compatible). Two alleles do not work together to make a single version of an enzyme. Each allele produces its own version of the enzyme, and you wind up with a mixture of two slightly different enzymes. If neither version of the enzyme works normally, then you don't get a normal-looking animal. That's the way it works when a himalayan mouse is crossed with an albino mouse. The albino mutant gene in the mouse produces a nonfunctional version of the tyrosinase enzyme. The himalayan mutant gene produces a partly functional version of the tyrosinase enzyme. Crossing an albino and a himalayan produces a mouse that has some pigment but not as much as a homozygous himalayan.

As far as I know, the tyrosinase test is not particularly difficult to do. The hardest part would be getting skin samples from the right boas.

Paul Hollander

I guess I didnt think of it that way. I was thinking that the effect would only happen if the individual had two alleles with the same mutation forgeting the fact that neither allele would be wild type and able to be dominant over the mutated allele.
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- Jason F.

is not considered a Dominant trait. It would be co-dominant, seeing that their is a distinguishable difference between the Jungle & Super Jungle.....
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Chris & Alliey
www.bloodyleopard.com
E-mail Us

Jungle is Co-dominant.

Here are a few more mutations to add to your list.

Sharp Albino-recessive-lack of melanin in the phenotype

Aslo distinguish between different forms of Tyrosinase positive Albinos.

Caramel Hypo (Boawoman Hypo)-recessive-a Hypomelanistic trait with similarities to Colombian T-plus Albinos and Pastels.

European Squaretail-Recessive-long list of variable characteristics

Scoria-unknown, believed to be recessive. A Pink patternless boa with two parrallel lines down the back

Blood-recessive-a Hypererythristic mutation

Leopard-Recessive-dark color, a mix of underlying tones and marbled pattern.

Aztec-dominant until a Homozygous is produced to prove it.

Grey Patternless-unknown

Type II Anerythristic-recessive-possibly also axanthic

Pewter-Double Homozygous Type II Anerythristic and Blood

I am certain I left more out. Do make a distinction between different forms of Hypomelanism, T-plus Albino, Amelanistic, and Anerythristic.

Dear Dave, while technically correct, this is confusing and could be stated better if you expect this to be helpful for newbies. They are going to need to know what a het is way before they understand what a gene pair is or even that genes come in pairs. Maybe you could avoid this is you defined gene first? Maybe you could solve it some other ways too.

"...Het = heterozygous = having two different genes within a gene pair. Most commonly one normal and one mutant but could be two different mutant genes..."

just my .02
Caden