Lethal Factor

[Pookinaround]

I am wondering if anyone knows exactly why the lethal factor happens with TOV X TOV & White x White breedings??? Any links to articles would great! What I am looking for is basically a biology lesson on WHY it happens. No specific reason other than just wanting to understand it better...THANKS!!!

 

[AZChins]

It's because the genes for TOV and for white cannot exist in the homozygous state. It could be that it just is impossible for the genes to exist and it is impossible for any babies to be conceived as homozygous TOV or white. OR, the babies with homozygous TOV or white die early on. I've heard people say that the lethal factor is simply a theoretical way of explaining why there is no homozygous TOVs or whites, but I have also heard that homozygous babies are conceived but die and are absorbed early on in pregnancy and there are less babies born.

 

[RDZCRanch]

What we know of the lethal factor is taken from rabbits and rodents that have similar instances of homozygous lethality. In other mammals, when a lethal allele is in the homozygous state, the animal dies early in the womb during embryotic development and is either aborted or reabsorbed. This occurs once fertilization has occurred and those two alleles come together...if the two alleles don't come together, there is no lethality. Since we never see any homozygous babies born, we assume chinchillas have an embryonic homozygous lethality.

Here is an embryonic lethality in mice.
http://genesdev.cshlp.org/content/7/7a/1203.short

 

[Pookinaround]

Hey thanks Tabitha!