# Thoughts I must share (boa genetics)



## Dexter (Jun 24, 2005)

If I bred 100% het albino x 100% het albino, I'd get (out of 20 babies):

5 albinos (25%)
10 100% het albinos (50%) 
5 commons (25%)

However, often boas have slugs and still borns. So let's consider that we get 4 slugs and 4 still borns, we would have:

7 albinos = 5 snakes + 1 slug + 1 still born
14 100% het albinos = 10 snakes + 2 slugs + 2 still borns
7 commons = 5 snakes + 1 slug + 1 still born

But nature can't be this perfect all the time, so I was wondering if I'm very lucky that I could end up having:

7 albinos
13 100% het albinos
4 slugs (commons)
3 still borns (commons)
1 still born (100% het albino)

Although I'd not be able to tell the 100% het albinos were 100% het or commons, I'd still have a litter with 7 albinos and 13 66% het albinos.

Do it make any sense ???


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## sami (Oct 23, 2006)

yes that is exactly what happens.

the nubers are completely random. you can figure out what you can statistically expect to receive but these averages are not often played out in one litter.

your litter could be anything from all visual albinos to none and anything in between.

With each neonate/egg you have you apply your chances to.

Mason


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## paulh (Sep 19, 2007)

Here is an analogy. The odds of getting a baby from a pair of hets is like throwing one die. Most dice have 6 sides, so you can use one of those. The 6 sides mean the following:
1 = homozygous normal
2 = heterozygous
3 = heterozygous
4 = homozygous mutant
5, 6 = do not count; throw again.

Use several dice per throw to save time by simulating several babies. Make a few sets of 20 dice and see how the actual results compare to the expected, theoretical results.


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## Dexter (Jun 24, 2005)

paulh said:


> Here is an analogy. The odds of getting a baby from a pair of hets is like throwing one die. Most dice have 6 sides, so you can use one of those. The 6 sides mean the following:
> 1 = homozygous normal
> 2 = heterozygous
> 3 = heterozygous
> ...


Nice, what's a homozygous mutant ? Is this the one that is not visual nor het, just a common ? And are the dice 5 and 6 the slugs and still borns ?

By the was, I'll do that now, and will tell you how many I go : victory:


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## Dexter (Jun 24, 2005)

These were my results (out of 20 throws):

1 - 5 times
2 - 5 times
3 - 3 times
4 - 1 time
5 - 2 times
6 - 4 times

Not too bad : victory:


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## Ssthisto (Aug 31, 2006)

Just remember that the 4 represents your homozygous albino animal... which means you only got one albino out of that lot of throws


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## Dexter (Jun 24, 2005)

Oh shit. Actually, when I was throwing the dice I had focused on the 1 as being the visual albino :roll:

But I've just through the dice again, and it was incredibly even ...

1 - 3 times
2 - 2 times
3 - 6 times
4 - 3 times
5 - 3 times
6 - 3 times

Just a shame we can't decide the fate of our snakes by just throwing dice :crazy:


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## paulh (Sep 19, 2007)

Homozygous mutant means there are two copies of the mutant gene in the gene pair. These have the full mutant appearance.

Homozygous normal means that there are two copies of the normal gene in the gene pair. These look and are normal.

Heterozygous means that there is one copy of the mutant gene and one copy of the normal gene in the gene pair. 

For the heterozygous: If the mutant gene is recessive to the normal gene, then the animal looks like the homozygous normal. If the mutant gene is dominant to the normal gene, then the heterozygous animal looks like the homozygous mutant animal. If the mutant gene is codominant to the normal gene, then the heterozygous animal looks different from both the homozygous mutant animal and the homozygous normal animal.

The numbers 5 and 6 are not counted. If a 5 or 6 turns up, throw again until a number in the 1-4 range comes up.

Dexter threw
1 - 3 times
2 - 2 times
3 - 6 times
4 - 3 times
5 - 3 times
6 - 3 times

Delete the 5s and 6s. That leaves 14 throws (babies) -- 3 homozygous normals, 8 heterozygous, and 3 homozygous mutants. The theoretical, expected results are 1/4 homozygous normal, 2/4 heterozygous, and 1/4 homozygous mutants. So these observed results are close but do not exactly correspond to the expected result.

Dexter threw
1 - 5 times
2 - 5 times
3 - 3 times
4 - 1 time
5 - 2 times
6 - 4 times

Delete the 5s and 6s. That leaves 5 homozygous normals, 8 heterozygous, and 1 homozygous mutant out of 14 babies. These results are a little further away from the expected results than the other set of babies were.

The difference between the observed and expected evens out over many series of throws. That is why a man can win 50 million dollars in the lottery, and the lottery still posts a profit at the end of the year.


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## Herpinfested (Apr 24, 2007)

so, what exactly is meant by the term slug?


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## paulh (Sep 19, 2007)

A slug is an infertile egg. It is usually smaller, more irregular in shape, and more yellow in color, when laid, compared to a fertile egg. A slug also often feels greasy.


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## paulh (Sep 19, 2007)

For boas, a slug is still an infertile egg. But it is a lot easier to tell a slug from a baby boa at delivery time than it is to tell a slug from a normal egg in egg-laying snakes.


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## Dexter (Jun 24, 2005)

Herpinfested said:


> so, what exactly is meant by the term slug?


 
I'll try to illustrate that, to make your life easier.

This is a litter of boas:



These were slugs that came through with this litter:



These were still borns:


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## Dexter (Jun 24, 2005)

Thanks for your help Paul.

Let's hope I get lucky the day I manage to breed my hets : victory:


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