Emily Forrester <[EMAIL PROTECTED]> wrote
>But ... what if a person produces a DPP gerbil, then outcrosses it to an
>unrelated gerbil. Then crosses a resulting pup either back to the DPP
>parent, or if possible, another unrelated DPP gerbil if available. Then if
>DPP pups are produced from that pair the process could be repeated, widening
>the pool of DPP and hopfully DPP carriers slowly.
We tried this but it was very slow as the fatality rate amongst gerbils,
not just DPP ones, descended from these crosses was so high we decided
it was not a good idea. The mutation in the US seems less dangerous and
I wish them luck in getting it established.
The problems did not see to be based on a recessive gene as we bred
three different pairs where only one member was from the same parents as
at least one DPP. Some of the pups were DPP but all the litters were
badly affected by the health and growth problems I described.
Other descended gerbils without DPP bred successfully and have had
normal offspring.
My theory is that the mosaicism was caused by an inherited inability to
correctly repair DNA. This lead to animals displaying patches of colour
that suggested that Sp was mutating to unspotted in parts of the body.
The problem is, of course, that if this inability to repair DNA is
carried out throughout the body, vital systems will be affected.
>
>Now, what about the DPP trait itself? It seems to me from what I've heard
>that this trait is associated with gerbils that are Cch.
Not the ones we saw, and still have.
>The cases I have
>heard of within the last several months are from pairs that have the
>potential of producing Cch gerbils. Are there any theories that the trait
>could be linked with gerbils that are Cch?
All DPP gerbils were Sp+. They were lilac pied, black pied and argente
pied. The reason it appears that Cc[h] is involved is that a pied lilac
looks lighter, like a dove, so an unspotted patch on such an animal
appears lilac coloured. The shift from lilac to dove is an illusion. The
argente was difficult to see, although black DPPs can also be difficult
to see, it is more obvious if the patch is on the belly as the black fur
is often a little lighter here.
As far as I am aware there was no c[h] in any of the animals we bred.
>
>It also seems to me that because of the few gerbils that are produced with
>this trait (DPP) that it could be a recessive trait, possibly linked with
>other recessive traits. Is there any evidence that it is a recessive trait
>versus a dominant trait?
I don't think DPP is indicative of either. From what I have seen the
problem that underlies it is not recessive, but that this does not
always express itself as DPP for the reasons I gave above. Other systems
could be affected but melanoblasts may not be, for example.
I realise that none of this may apply to the US DPPs, but a mechanism
that causes this sort of mosaicism would be expected to have other
effects.
--
Julian
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* Jackie and Julian *
* [EMAIL PROTECTED] *
* National Gerbil Society *
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