# Crossing Cherry with Wild Neocaridina heteropoda



## Dwarfpufferfish (May 29, 2004)

About 2 weeks ago I started an experiment to find if the red color of a cherry shrimp is a double recessive gene and if it is sex linked. You can follow all the information on my websites blog (link in signature).

Today I witnessed the first behavior that would suggest breeding in the tank that has a male cherry shrimp and a female wild type Neocaridina heteropoda. The male was swimming around the tank franticly only stopping to hang out with and touch the female.

I was also able to snap a picture of the pair together so I figured I would share it here.










I will post more updates when the female becomes berried.

Questions and comments are welcome.


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## Madfish (Sep 9, 2007)

Thats a great idea that you have. Please keep us all up to date on it. Thats I'm a little crazy about crossing things to see how they turn out.


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## swylie (May 10, 2007)

I'm excited by your project. That said, don't be surprised if inheritance of red coloration is linked to a large number of genes. If that's true, this will be a complicated project because you'll need to breed many more shrimp.

I'd bet there are half a dozen or more factors that control the production of red pigment. We know that males are less red than females of essentially the same genotype, so sex must be one factor regulating the red pigment pathway. We also know that some females out there are redder than others. Is this an issue of variable expressivity? Is it because some people have healthier shrimp? I suspect that it is neither because it's generally acknowledged that people have selectively bred strains that are very, very red (not just expressivity, though that certainly plays a part) and that these shrimp stay pretty red in other people's tanks. (not health)

Also, don't shrimp change color with their mood? Happy shrimp are redder than stressed shrimp. Adult shrimp are substantially redder than juvenile shrimp. Those are two more ways off the top of my head that I can think of that shrimp coloration is regulated.

That said, a bunch of those things I just listed probably apply to brown shrimp too, and would affect total pigment production, not just red pigment production. It's certainly possible that redness is a simple double recessive. This is fun to think about, and I look forward to your data.


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## Madfish (Sep 9, 2007)

This has got me thinking what if you could cross a red cherry and a white snowball? Insteed of a crystal red you could have a red crystal.


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## dhavoc (May 4, 2006)

eventually, you will end up with all wild form, but reds will pop up every so often. i have several 5-10 year old wild neo populations in several tanks, and i accidentally added some rcs to one of the tanks before i figured out they were the same species. they interbred and eventually all offspring reverted to wild form colors. that said every so often a red one (as red as a true RCS, not reddish like the wild form can exibit) will appear in the tank. the gene is still there but its recessive so only a small number will ever exibit the trait again.

that said, it would be interesting to find out which one if anything determines the red color (sex or double recessive).


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## Dwarfpufferfish (May 29, 2004)

Well just so everybody knows a little background here, my wife and I both have marine biology degrees. Neither of us work as marine biologist as we have both found that a career in that field does not really put food on the table! But we both are hobbyist.

I understand that there is the possibility that the red color is linked to many genes but I am trying to make this experiment as user friendly to the shrimp hobbyist as possible. One thing I find is that in the Dwarf Shrimp hobby there is little accessible information. So I figured I would start with the most popular shrimp and go from there.

Now some thoughts…

The males ARE less red than the females, but that does not mean that the trait is sex linked. It is displayed in both male and females, so it just maybe sexual dimorphism. But, then again, it may be sex linked. Genetics are crazy complicated, but sometimes it is just as simple as being a double recessive. I do not plan to research this all the way down to the DNA level, but just plan to find how the trait is passed from generation to generation.

MADFISH:
This is not crazy; both of these shrimp are the SAME species. They are both Neocaridina heteropoda. The offspring will not be hybrids; they will just be less colorful than the parents. I would never recommend crossing a Snowball (Neocaridina cf. zhangjiajiensis) and a Cherry Shrimp (Neocaridina heteropoda). They are different species and would result in a hybrid. And odds are that if they breed (good chance they could) that you would end up with a wild type shrimp. Both the white and the red are a recessive trait, and odds are since they are different species the color traits are linked to different genes (although it is possible they are linked to the same, like I said earlier genetics are crazy complicated). But at the end of the day, they are your shrimp and if you don’t plan on selling the offspring under false names or releasing them into the wild, do what you wish!


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## Dwarfpufferfish (May 29, 2004)

Dhavoc:
What has happened with your shrimp shows only that it is a recessive gene. When you introduce a small amount of shrimp that carry the Red gene with a large amount that do not, odds are the Red will be expressed in offspring very infrequently.

Here is what I hypothesize happened in your aquarium. I think the red trait of the cherry shrimp is a double recessive gene, we will represent this with a lower case “r” and the wild color trait as a dominant gene, we will represent this with a uppercase “R”.

Now for a Neocaridina heteropoda to express the red trait they must have the “rr” gene, and to express the wild color they can have either “RR” or “Rr”.

When you introduced a small amount of “rr” (cherry shrimp) to your tank what happened was they bred with the “RR” (wild type) and genetics says all off spring would be “Rr” (wild type carrying the recessive gene for the red color). 










Now because your wild population out numbered your cherry population I would guess the F1 (first generation of offspring from the cherry/wild cross) would mostly mate with the wild type shrimp. This would be an “Rr”/”RR” cross.










This shows that 50% of the shrimp that resulted from this cross do not carry the “r” (red color gene) and 50% of them do but do not display the color.

Of course every now and then there is going to be a cross between the “Rr” and “Rr” shrimp.










This shows that 75% of the offspring would carry the red trait and not display it and 25% would display the red trait (cherry shrimp).

So after time, you will end up with a population that mostly displays the wild type coloration but on the occasion a Cherry Shrimp will pop up!

Now genetics are way more complicated then shown above, and most times mother nature doesn’t care what percentage of recessives should be born and gives a much lower number. But that is the basics of what I believe happened in your tank. And really is the foundation of the experiments I am conducting.


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## swylie (May 10, 2007)

Dwarfpufferfish said:


> Well just so everybody knows a little background here, my wife and I both have marine biology degrees. [...] The males ARE less red than the females, but that does not mean that the trait is sex linked.


Yeah, good to know, if you're that prepared for the project than I may have sounded patronizing. Anyway, I didn't mean to suggest the trait is sex-linked. I'm just pondering whether this is more analogous to, say, human height or human blood type inheritance.


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## eon17 (Aug 30, 2007)

how are new color morphs created of these shrimp?


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## Dwarfpufferfish (May 29, 2004)

New color morphs are not really “created”. The two color morphs that are most popular (red and yellow) are not found in the wild for one main reason. They would not survive. Predators would find them easily and eat them.

So how do they come to be in the aquarium hobby? If the color is a double recessive, as I believe it to be, the first red/yellows to appear are most likely the result of two shrimp that have bred both carrying the recessive gene.

There is also the possibility of spontaneous mutation. That is when a gene mutates and the result is the new color shrimp. Somewhere in the history of this species this had to have happened for the new colors to show up. Of course it is much more complex than this, but that is the basics.


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## Madfish (Sep 9, 2007)

Sorry I was just trying to be a smart a$$ thats all. But I am very intrested in finding out how it turns out.


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## eon17 (Aug 30, 2007)

I know that much i eamn are they just found in someones tank of wilds some day? you couldnt breed for a trait you dont know exists


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## dhavoc (May 4, 2006)

yep, thats what i assumed happened with my population as well. was an expensive mistake on my part though (shows one should always research well before mixing things). my wilds display many different colors and even stripes, but i found that color etc, in the wild form anyway tend to be affected more by environment than genetics, they are true chameleons and will change color to better match the habitat. a good survival trait to have, also makes selective breeding for color much harder as well. which is why i dont bother with mine, even though others have suggested i do so for the the striped ones, i think it would be a waste of time, for me anyway.

good luck with the experiment.


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## eon17 (Aug 30, 2007)

oh man breeding for stripes would be fun!!


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## fishymatty (Feb 25, 2007)

Do you know anything about the breeding of cherry shrimp from wilds? What I mean by that is how RCS were originally bred? That info might help. IME all you get is more brown shrimp.


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## Dwarfpufferfish (May 29, 2004)

I do not have any direct reports of who or how the original cherry shrimp was found. I would guess it was either the result of two browns carrying the double restive gene or a spontaneous mutation. This experiment will determine that.


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## eon17 (Aug 30, 2007)

well you hope it will!


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## Dwarfpufferfish (May 29, 2004)

Well, by doing this experiment I will be able to find out if it is a recessive gene, or a combination of them. If the red color shows up in future generations after crossing F1 with F1 it will prove that it is a recessive gene.

Will it prove 100% if it is more than one gene that the color is linked to, no, not at all. But it will prove that it is a recessive gene and I suspect it is a double recessive. If the color does not show back up, it is obviously something else and more experiments will have to be done.


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## A Hill (Jul 25, 2005)

fishymatty said:


> Do you know anything about the breeding of cherry shrimp from wilds? What I mean by that is how RCS were originally bred? That info might help. IME all you get is more brown shrimp.





Dwarfpufferfish said:


> I do not have any direct reports of who or how the original cherry shrimp was found. I would guess it was either the result of two browns carrying the double restive gene or a spontaneous mutation. This experiment will determine that.


From what I've read, it was a freak accident. Two Wilds having the right genes at the right time. Supposedly it occurred in a German's tank.

I also read about the experiment of putting wild form cherries into a tank that everything was red... fake plants gravel, background.... and there being predators in this tank. Neons, Cardinals.. something big enough to eat them but small enough to not eat them all... 

Over the course of a year or many months the shrimp where much redder than the control tank.

Another interesting thing I've seen in my cherry tank, is yellow tinted males:icon_smil they sure are good looking 

Good luck,
-Andrew


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## Dwarfpufferfish (May 29, 2004)

Well it makes sense that the red shrimp would be the ones to survive in that environment. They are the most camouflaged, and that is the reason that cherry shrimp are not found in the wild, they do not blend into anything and are easy prey. So all the wild type offspring in an all red environment were easy prey, the red were harder to find.

I would love to see pictures of your yellow tinted males! Do you have any?


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## A Hill (Jul 25, 2005)

Dwarfpufferfish said:


> I would love to see pictures of your yellow tinted males! Do you have any?


Not at the moment, They're in a 55g tank, and I don't have a great camera. Maybe if I get to separating them out of the tank I'll post some pictures. Basically it's like a cross of a yellow shrimp, and a male RCS, has the red 'lines?' and a yellow tint/undertone

-Andrew


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