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Post by Admin on Feb 16, 2008 23:53:24 GMT
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Post by Loz on Feb 17, 2008 0:01:58 GMT
Very nice Ed and Eli ;D
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Post by peppercarnage on Feb 17, 2008 3:36:47 GMT
that is a great guide  but i'm confused about the last few slides. if Sp is a dominant, lethal gene, then how can a gerbil be a carrier? or does that refer to a gerbil carrying the modifier genes that extend spotting in Sp gerbils? sorry if that's an elementary question. aaand how on earth did you get your gerbs to sit belly-up long enough to take a photo?  |
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Post by Mermum on Feb 17, 2008 8:19:52 GMT
Dominant means that if a gene appears it's characteristics will always appear in the phenotype (ie what the animal is physically like).
Sp is odd in gerbils in that there is no equivalent recessive at that loci, a gerbil either has Sp or doesn't). So on conception the embyro is either Sp or SpSp.
Embryos with SpSp are not able to divide properly (Ed can probably explain what happens if needed) and cannot therefore implant.
Because this happens so early and gerbils produce more embryos than can implant anyway the number of pups in the litter is not affected.
We use the prenatally lethal, effectively we are saying that SpSp embryos never survive. Because SpSp is lethal so early there is no problem with breeding two Sp gerbils together.
I hope this simplified explanation helps you understand what is happening.
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Post by Admin on Feb 17, 2008 19:00:33 GMT
What breeders term a "dom spot carrier" is the solid type gerbils coming out of spotted lines, but these gerbils carry the white modifying genes for either spot, collared or mottled varieties. If you cross a "carrier" from any of these lines to other spotted varieties you'll get those modifying genes affecting the crosses.
Also with these varieties, the amount of white on their bibs or feet often reflect what type of modifiers they have i.e. the more white they possess is often an indicator as to whether they'll produce spot, collared or mottled types.
Ed
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Post by peppercarnage on Feb 17, 2008 21:55:10 GMT
ah okee thanks |
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Post by Admin on Feb 18, 2008 20:20:13 GMT
I've just updated the pages with more info on the dom spot "carriers" plus mottled and EW comparison pics as well.
Ed
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Post by Loz on Feb 18, 2008 20:25:16 GMT
Very nice Ed ;D Comparison pics of EW gerbils and dominant spot mottled gerbils really shows up the differences.
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Post by Indyrascal on Feb 18, 2008 21:08:24 GMT
I wish my brain would allow me to understand any of this  |
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Post by peppercarnage on Feb 18, 2008 21:40:11 GMT
the mottled vs EW pics are great, very subtle differences between the two i never would have figured out myself |
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domination.
