Dwarfing Gene Clarification

[pamnock]

Wanted to clear up some misinformation posted on a previous thread:

The Achondroplasic Dwarfing gene that we most commonly see in rabbitsis dominant, not recessive as Austin stated. (He would haveknown that if genetics was indeed his major and profession as he statedbecause the Achondroplasic Dwarfing gene is one of themostcommonly inherited forms of human dwarfism -- any geneticist would knowthis).

As a real geneticist stated: "Anchondroplasia is not compatible withlife" -- So, yes -- the condition of the "double dwarfing gene"(peanuts) is fatal. However, there are less common forms ofdwarfism that are not fatal in the homozygous state. Therehave actually been over 200 forms of dwarfism identified in humans!(Which explains why all runts do not die).

Can the Dwarfing gene be bred out of dwarf lines? Yes -- butthen you will not get the desired dwarf characteristics of that breed.

The previous thread on this subject was locked -- so I would appreciateit if no replies were posted here -- I just wanted to correct somemisinformation. If anyone had further questions, they can PMme.



Pam

 

[Carolyn]

Thank you, Pam!



I don't mind discussion about it at all. I locked itbecause it was goingtoo far offtrack that hadnothing to do with the subject at hand. The same troll keptcoming back under different names.




-Carolyn

 

[pamnock]

Carolyn wrote:

Stop that you silly woman -- it's a long, hardfall down -- and my bones are getting to brittle for that LOL

Pam

 

[Starlight Rabbitry]

Thanks for the clarification Pam. Inever really thought about the runts like that. A questionfor you...If I get a runt in a little of Dutch, does that mean that ita form of a dwarf or what? Sorry, I am slightly confusednow. Thanks, Sharon

 

[pamnock]

Sharon,

There are many genes that regulate conditions such as growth, failureto thrive, SIDs, etc. Some of the genes associated with theseconditions have been mapped and identified, others have not.Even though a gene has been mapped, its actual purpose and interactionwith other genes may not be known.

Not all "runts" are a result of the Achondroplasic Dwarfing gene --there are thousands of other genes responsible for growth/sizeregulation. The Achondroplasic Dwarfing gene causes majororgan failure within a few days of birth -- death is often a result ofrespiratory failure. Insome cases the lethal dwarf"peanut" dies in utero and is reabsorbed.

Pam

 

[Starlight Rabbitry]

Thanks Pam! I think I get itnow. I am trying to learn about genetics but it is veryhard. Trying colors right now. Thanks again.

 

[BlueGiants]

Thank You! I could use someclarification too. I was lead to understand that runting wasnot the same as doubledwarfing.Ithoughta RuntDutch/Palamino/Californian/ etc. was not a "dd" geneticDwarf. I was told that runts are caused by developementalproblems in utero... affected by anything including age of mother,nutrition levels, size of the litter, condition of the mother,etc. And I thought the "dd" was strictly genetics.And "dd" is always dominant and always fatal. I would soappreciate any information, either supportive orcontradictory. Thanks

 

[pamnock]

BlueGiants wrote:

Thank You! I could use some clarificationtoo. I was lead to understand that runting was not the sameas double dwarfing.Correct -- differentgenes.

Ithoughta RuntDutch/Palamino/Californian/ etc. was not a "dd" geneticDwarf. I was told that runts are caused by developementalproblems in utero... affected by anything including age of mother,nutrition levels, size of the litter, condition of the mother,etc. Also correct to some extent-- environmental factorscan play a role as well as genetics. However, more genes arebeing mapped that are associated with these conditions. Evenin this day and age, there is still more that we "don't" know aboutgenetics than we do know.Remember thatthere are thousands of genes that have been linked to small stature --small size is not always due to the Anchondroplasia Dwarfinggene.

And I thought the "dd" was strictlygenetics. And "dd" is always dominant and alwaysfatal. I would so appreciate any information, eithersupportive or contradictory. Specifically, Anchondroplasiais a genetic mutation. Remember that it is Dw (dominant) --dw is the recessive normal/large.

Pam

 

[BlueGiants]

Appreciate the clarification andexplaination. I guess we'll just have to wait for theresearch to "catch-up".

 

[Jenniblu]

So basically - A peanut (double dwarf gene) isalways a runt (small), but not all runts (small)are peanuts(double dwarf gene)?

 

[pamnock]

Jenniblu wrote:

So basically - A peanut (double dwarf gene) is always a runt(small), but not all runts (small)are peanuts (double dwarfgene)?

Correct -- specifically, the Achondroplasic Dwarfing dominant gene inthe homozygous state produces a very tiny rabbit with domed head,protruding eyes and under developed hindquarters as well as lethalhealth problems.

Not all runts are small in size due to the homozygousAnchondroplasic Dwarfing gene. Some are heterozygous (notlethal), where others have inherited a completely different genealtogether.

Pam

 

[Lazyacre]

I always saw it as an incomplete dominance,since in the hetero state (Dwdw) you see only some action of thedwarfing genem while in nhomo state (DwDw) there is complete action ofthe gene. If there was full dominance i'd expect that the Dwdw would besame as DwDw.

 

[Jenniblu]

pamnock wrote:

Jenniblu wrote:

So basically- A peanut (double dwarf gene) is always a runt (small), but not allrunts (small)are peanuts (double dwarf gene)?

Correct -- specifically, the Achondroplasic Dwarfing dominant gene inthe homozygous state produces a very tiny rabbit with domed head,protruding eyes and under developed hindquarters as well as lethalhealth problems.

Not all runts are small in size due to the homozygousAnchondroplasic Dwarfing gene. Some are heterozygous (notlethal), where others have inherited a completely different genealtogether.

Pam

Gotcha! :yes:

 

[Lazyacre]

pamnock wrote:

Jenniblu wrote:

So basically- A peanut (double dwarf gene) is always a runt (small), but not allrunts (small)are peanuts (double dwarf gene)?

Correct -- specifically, the Achondroplasic Dwarfing dominant gene inthe homozygous state produces a very tiny rabbit with domed head,protruding eyes and under developed hindquarters as well as lethalhealth problems.

Not all runts are small in size due to the homozygousAnchondroplasic Dwarfing gene. Some are heterozygous (notlethal), where others have inherited a completely different genealtogether.

Pam

An example of the latter would be the American Polishrabbit, this breed of 3# rabbit was around before the Netherland Dwarfmade it's appearance and didn't have a dwarfing gene until some crossedthem with the ND.

 

[pamnock]

Lazyacre wrote:

An example of the latterwould be the American Polish rabbit, this breed of 3# rabbit was aroundbefore the Netherland Dwarf made it's appearance and didn't have adwarfing gene until some crossed them with the ND.

Exactly! Although very small, the Polish does not have theclassic Achondroplasic gene rounded Dwarf head, nor do "pure" Polishproduce lethal "peanuts".

Pam

 

[Lazyacre]

Yes. When we raised Polish we'd occasionally come across lines that produced peanuts, we then knew ND was crossed into them.

 

[BlueGiants]

I have another question, do you think that theDwarfing gene originated from the Netherland?The"dd" seems to be prevelant in the Mini Rex...could they havebeen crossed with ND's? Is the "dd" a gentic mutation (wayback when?) that was cultivated (similar to the rex fur)?

Really appreciate your time.

 

[pamnock]

BlueGiants wrote:

I have another question, do you think that the Dwarfing geneoriginated from the Netherland?The "dd" seems to beprevelant in the Mini Rex...could they have been crossed withND's? Is the "dd" a gentic mutation (way back when?) that wascultivated (similar to the rex fur)?

Really appreciate your time.

In the US, the designation "dd" is the genotype for a homozygous blue rabbit.

"dw" is used in the US to represent the normal sized rabbit and "Dw" isthe designation for the dominant dwarfing gene common in the NetherlandDwarfs.

This genewould have beenpresent in thewild European rabbits that the Netherland would eventually be developedfrom.



Pam

 

[Lazyacre]

BlueGiants wrote:

I have another question, do you think that the Dwarfing geneoriginated from the Fatherland?The "dd" seems to beprevalent in the Mini Rex...could they have been crossed withND's? Is the "dd" a gentic mutation (way back when?) that wascultivated (similar to the rex fur)?

Really appreciate your time.

the Mini Rex was indeed developed from a dwarfrabbit.In 1984 arex furred dwarf was crossed with astd Rex doe and the resulting litter were line bred to become the firstMini Rex. many breeders made their own MR crossing std Rex and ND. Aspam said dd is used here for Dilute Color (Blue or Lilac), DD is DenseColor (Black or Chocolate). The Dwarf gene was cultivated from theEuropean Rabbit, making the Netherland Dwarf, which has been usedtomake many subsequent small breeds. Rex mutation wasdiscovered in a French litter around 1920 or so.

 

[BlueGiants]

Sorry for the incorrect label... Thanks for the answer.