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Cool, too bad they both are not making it.

melissa68 said:
I have noticed this a few times with our vent eggs, but usually the egg goes bad. This time, one of the twins is developing & the other has stopped.

I thought you would find this interesting!

Can you see it in the middle?



Melissa
 
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'twins'

I have had many occurances of this in my vents and a couple of times in tincs/azureus. Some of them would end up like Melissa's and one would terminate, yet not affect the other. I have also had quite a few of these vents turn out perfectly fine and larger than the rest of the clutch mates. I strongly believe that these are 2 embryo that share an outter membrane and appear to be in one single egg, when actually they are 2 eggs conjoined. If you look closely, you will see the cleavage and the conjoined area and see the membrane seperating the 2. Chances are, if the membrane is strong enough, the decomposition of the terminated embryo will not affect the surving embryo. Just some rambling on my experiences with this.

-Bill J.
 

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I have seen this with my azureus before, and heard of it with several different species and bloolines. I don't think they could really be considered twins though. Twins split from one egg. At least from what I've seen they are two different eggs just sharing the egg casing. Even if the eggs were once a single eggs and split inside the female, before laid, being that fertilization is external, it would still take two seperate sperm to fertilize each egg. I think to have twins you would have to get two tadpoles forming on a single. Now that would be wild!!!
 

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khoff said:
I don't think they could really be considered twins though. Twins split from one egg. At least from what I've seen they are two different eggs just sharing the egg casing. Even if the eggs were once a single eggs and split inside the female, before laid, being that fertilization is external, it would still take two seperate sperm to fertilize each egg. I think to have twins you would have to get two tadpoles forming on a single. Now that would be wild!!!
You can actually artificially create "identical" twin frogs through an unusual mechanism of developmental biology. By utilizing a blond hair as and tying a noose of sorts, you can actually carefully separate an equal number of cells at the stage where the number of cells equals 8-16, but before the blastocyst is formed. You are actually pinching the fertilized cells's outer membrane to separate the two "halves" of cells. From this point, a small percentage of the time you will have both groups of cells begin to form a separate tadpole, each containing identical genetic material.

I've seen this done utilizing american bullfrog eggs as a method of studying what developmental molecules affect the "switching" on and off of gene expression. I've never heard of it being tried in darts, but I don't see why it wouldn't. By the way, you use a blond hair because it has the smallest circumference of the various colored hairs, not because I'm pulling your leg. This really does happen.

P.S.--even if two different sperm fertilized a two-nuclei egg, I think they would still be fraternal twins. Of course, it depends on how the two nuclei were formed.
 

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Very interesting topic. I would imagine MANY of the test eggs, would go bad. I'm bet nobody is willing to risk these egg losses. Not to mention, bullfrog eggs are believable but freshly laid dart frog eggs are extremely small. One would have to have precise control of blonde hair to get it even close to two equal halves. Thanks for the informative post.
 

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It's funny, I was just thinking of posting about the same "twinning with human hair" method. I have preformed this procedure with Xenopus eggs in a development lab class a number of years ago. When you split the egg, each new half does a few rounds of extra cell divisions to make up for the lost material. I managed to get developing embryos, but nothing to survive to hatch as a tadpole. I think our sterile technique was in question, which is a critical part to the success of this procedure. Ultimately, unless you perfect this technique it might be hard to break even.
 

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twins

This is funny. Bill has done this with bullfrog, Will with xenopus, and I have done this with gray tree frogs. The whole hair thing works pretty well. I tried this out during my research last summer- definately interesting.

Justin
 
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