# Het markers..................



## lawrencet1988 (Jan 2, 2010)

So, lets say you breed a normal ball python to a het ghost how will you tell if the resulting offspring is het or not? 
Will all of them carry the het 'markers' or will only the het ones?


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## Magpye (Jan 26, 2007)

If ghost is recessive then you won't be able tell by observation alone from a pairing with a normal, which of the normal looking offspring are het for ghost.


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## bothrops (Jan 7, 2007)

With recessive genes it is impossible to tell as _by definition_ recessive mutations have NO effect on what the animal looks like in the heterozygous form.

'het markers' wouldn't be 'het markers' if they were found in normal animals as well, however technically, if a 'het marker' is proven to exist then that mutation should be reclassified as 'co-dominant' as the heterozygote form is phenotypically different from the homozygous wildtype.

Cheers

Andy


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## paulh (Sep 19, 2007)

In an ideal world, only codominant mutant genes can be identified when heterozygous. Unfortunately, this is not an ideal world. There are mutant genes that produce a marker in maybe 5-10% of the heterozygous animals. And the rest of the heterozygous animals look normal. For these, the only way to tell is by a breeding test.

So where do you draw the line between a recessive mutant gene and a codominant mutant gene? 

IMO, if a person with 10 minutes training can identify the heterozygous animals with at least 95% accuracy, then the mutant gene is a codominant mutant gene. 10% accuracy is way too low.

Just be warned that many so-called "het markers" are coincidence and not cause and effect. As far as I know, there are no het markers for het ghost royals.


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## lawrencet1988 (Jan 2, 2010)

What about het pied markers? are there only het markers for some recessive traits?


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## Ssthisto (Aug 31, 2006)

The "het pied" markers are not a guarantee.

Not all het pieds have the markers.
Not all animals that have the markers are in fact het pied.

Now, yes, the markers do seem to be relatively common in het pied - but that could be because there's a "tagalong" gene that's not actually related to pied but has been inadvertently selectively bred for in the course of people getting pieds, rather than being an actual indication of het-pied. The sort of idea being if you think that het pieds HAVE train track markers, you're more likely to choose a "possible het pied" with strong train track markers, and breed that, and if it proves to be het pied that "confirms" your belief that het pieds have strong train track markers, so you're more likely to breed it to another strongly marked animal...


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## lawrencet1988 (Jan 2, 2010)

Ok so basically then het markers mean nothing. 
Back to what i originally said then, there is no way of telling a 50% poss het from a 100% if the offspring is from het to normal breeding.


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## Ssthisto (Aug 31, 2006)

That's right, other than breeding it and getting an offspring of the morph in question (always assuming the morph in question is recessive).

Breed a possible-het-ghost to a Ghost, and get a ghost offspring out, and you've now proven that your possible-het is a definite het.


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## bothrops (Jan 7, 2007)

lawrencet1988 said:


> Ok so basically then het markers mean nothing.
> Back to what i originally said then, there is no way of telling a 50% poss het from a 100% if the offspring is from het to normal breeding.


 
They is no such thing as a '50% het' compared to a '100% het' in the same litter.

Animals are either het or they are not. Your litter will consist of some '0% hets' (i.e. completely normal) and some 100% hets. It is because you can't tell the difference between them, and that the maths tells you there should be around half of each, that they are ALL refered to as '50% hets' i.e. each normal looking animal has a 50% chance of being het or not!

If you could tell the difference there would be no need to label them as '50% chance of being het' (shortened to '50% het) as you could pick the hets from the non-hets visually.


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