Reptile & Amphibian Forums

I am not sure how black rat genetics work. So here is my question. The mother to my albino black rats was apparently white phase (won't know if it was genetic until I breed) So that should make my pair 100% het assuming it is genetic and not just an unusually clean albino. So once I breed my pair assuming they are 100% het white phase should I get 100% white phase offspring or some odd percent? I know I won't know anything until they breed but I am trying to figure out what to expect. Thanks for your time! -David-
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0.1 Snow Corn "Hope"
1.0 Ball Python "Wilson" (Castaway)
1. Orange Albino Black Ratsnake "Chunk" (Goonies)
.1 Orange Albino Black Ratsnake "Peaches"
0.0.1 Mexican Black Kingsnake "Onyx"

Your black rat is a regular albino, so you will produce hets. Then when bred back, you will get normal albino babies, which may show varying degrees of color, but all of which will be regular albinos.

I am not sure how black rat genetics work. So here is my question. The mother to my albino black rats was apparently white phase (won't know if it was genetic until I breed) So that should make my pair 100% het assuming it is genetic and not just an unusually clean albino.

This is a common misconception. Just because something is carried in the genes and is heritable doesn't mean it is inherited in a simple dominant/recessive type fashion. Many traits are show codominance, some are polygenic, some show epistatic effects, etc. The inheritance of many characteristics is more complex than the pattern shown by such simple characters as albinism.

If it is a separate trait, you should be able to produce non-albino "white-phase" snakes. I can't imagine what that would look like?

So once I breed my pair assuming they are 100% het white phase should I get 100% white phase offspring or some odd percent?

Assuming your snakes are albino, they will produce 100% albinos.
Assuming the "white-phase" thing is a simple dominant/recessive ,then you would produce this -
- 25% of the offspring should be white phase
- 75% should be normal looking albinos. Of the normal looking snakes, 2/3 should be hets for "white-phase".
Of course, you can't tell by looking at them which are hets and which aren't, so these are the snakes people describe (incorrectly, IMHO) as 66% hets. This means any individual has a 66% (2/3) chance of being heterozygous.

And of course, this is all dependent on the supposition that this white-phase thing is inherited as a simple pair of dominant/recessive alleles. This seems unlikely to me due to the nature of the way dominance works.
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Chris Harrison
San Antonio, Texas

Bam was right MY ratsnakes ARE albino but here is a pic of their mother and father.....

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0.1 Snow Corn "Hope"
1.0 Ball Python "Wilson" (Castaway)
1. Orange Albino Black Ratsnake "Chunk" (Goonies)
.1 Orange Albino Black Ratsnake "Peaches"
0.0.1 Mexican Black Kingsnake "Onyx"

I understand that they are albino and the inheritance of albino is very straightforward.

However, I though you were asking about the inheritance of the "white-phase".
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Chris Harrison
San Antonio, Texas

You asnwered my question perfectly Chris! the picture was to show Bam that they did in fact posses the genes for white phase if in fact their mother was genetically white phase.
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0.1 Snow Corn "Hope"
1.0 Ball Python "Wilson" (Castaway)
1. Orange Albino Black Ratsnake "Chunk" (Goonies)
.1 Orange Albino Black Ratsnake "Peaches"
0.0.1 Mexican Black Kingsnake "Onyx"

Let’s not get confused by our terms here. With a snake that has both the black/brown and the red/yellow skin pigment, it can express albinism in two ways. It can be amelanistic, or it can be anerytheristic. Sometimes it can be both.

A snake that is amelanistic produces little to no black/brown pigments. A snake that is anerytheristic produces little or no red/yellow pigment. Note that there are two mutations that can cause an animal to be amelanistic. So you can cross two amelanistic snakes and get all wild types, but those offspring would be 100% homo for both of the mutations.

The second snake pictured could easily be both amelanistic and anerytheristic, but you can’t tell for sure by a photo.

There is plenty of information our there on the web about the subject. Most of it deals with Red Rat Snakes, but the information applies to snakes in all of the P. obsoleti subspecies as well.

Good luck with your breeding projects.