Reptile & Amphibian Forums

But could someone please explain to me the basic genetics of a piebald? I have been thinking about getting a het male and het female but I don't understand how someone could claim they have a 100% het. If I understand this correctly, if you breed a piebald with a normal, each animal has a 50% chance of being a het right? How can one narrow that down to 100% if the snake has never been bred out to be proven? Also...if it is possible to get a male and female 100% hets....if bred together you would get all pieds right? I'm lost...I don't know.

The reason they are sure that is a hundred percent het for piebald is because the bred a piebald to a normal.. with each allele you need to traits one from the mother and one from the father.. Given this point either the mother or the father is the piebald so they have the both piebald genes.. so the offspring is gauranteed that piebald gene because that gene is the only gene that is carried by one of the parents.. Just look up the punnett square it will make everything alot easier

heres an example
aa(mother piebald)
AA(father normal)
AA
Aa Aa
aa
Aa Aa

so each offspring as one normal allele and one piebald allele

np

This is for pieds,albinos,ghosts,axanthics. I will use pieds as an example but works for the rest of the simple ressive snakes as well.
a pied bred to a normal gives you 100% het pieds
a het to a normal gives you possible hets.
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Thomas Jones
aligatorhunter@cox.net

When learning genetics, you need to understand that genes come in pairs. When the pair of genes can be selected from two different genes (call them A and a), there are three possible combinations:
AA = homozygous for A
Aa = heterozygous
aa = homozygous for a

When making sex cells (sperm or eggs), each sex cell gets only one of each pair of genes. So a snake that is AA only produces sex cells that are A, a snake that is aa only produces sex cells that are a, and a snake that is Aa produces sex cells with half of them being A and half of them being a.

When the sperm fuses with the egg, the result has a pair of genes again.

It might help to take some scraps of paper and write A on some and a on others. Then play around making combinations of two scraps.

When there are two possible genes to select from, there are six possible matings:
1. AA x AA - both make only A sex cells.
Result: all babies are AA.

2. AA x Aa - The AA parent makes only A sex cells. The Aa parent makes 1/2 A sex cells and 1/2 a sex cells.
Result: A joins with 1/2 A to make 1/2 of the babies AA.
A joins with 1/2 a to make 1/2 of the babies Aa.

3. AA x aa - The AA parent makes only A sex cells. The aa parent makes only a sex cells.
Result: all babies are Aa

4. Aa x Aa - both parents produce 1/2 A sex cells and 1/2 a sex cells. This is the tricky one.
Result: 1/2 A - 1/2 A makes 1/4 AA
1/2 A - 1/2 a makes 1/4 Aa
1/2 a - 1/2 A makes 1/4 aA
1/2 a - 1/2 a makes 1/4 aa
As gene order on paper makes no difference, Aa and aA are the same thing. The final result is
1/4 AA
2/4 Aa
1/4 aa

5. Aa x aa - The aa parent makes only a sex cells. The Aa parent makes 1/2 A sex cells and 1/2 a sex cells.
Result: a joins with 1/2 A to make 1/2 of the babies Aa.
a joins with 1/2 a to make 1/2 of the babies aa.

6. aa x aa - both make only a sex cells.
Result: all babies are aa.

Let's assign a to the piebald gene and A to the normal gene. A snake that is piebald is aa, a normal snake is AA, and an Aa snake is heterozygous piebald and looks normal. A normal to piebald mating is mating 3 above, and a het piebald to het piebald mating is mating 4 above.

And 100% het piebald simply means certainty that a normal looking snake is actually het piebald. Such snakes are produced in matings 3 and 5. Het piebalds are also produced in matings 3 and 4, but they are mixed with normals. In matings 3 and 4, there is a less than 100% chance that a given normal-looking baby snake is actually het pied.

Paul Hollander

>And 100% het piebald simply means certainty that a normal looking snake is actually het piebald. Such snakes are produced in matings 3 and 5. Het piebalds are also produced in matings 3 and 4, but they are mixed with normals. In matings 3 and 4, there is a less than 100% chance that a given normal-looking baby snake is actually het pied.

This should read as follows:
And 100% het piebald simply means certainty that a normal looking snake is actually het piebald. Such snakes are produced in matings 3 and 5. Het piebalds are also produced in matings 2 and 4, but they are mixed with normals. In matings 2 and 4, there is a less than 100% chance that a given normal-looking baby snake is actually het pied.

Paul Hollander