Truth or Myth

[randy]

We read many things on the internet, and some seems so true and some ridiculous. I always just put them in my mental note and hope to figure out my version of the truth .... or myth.

 

Have you read that if you mix CRS and CBS and eventually the colour will go toward brownish and red won't be so red and black won't be so black?

 

I just used this picture from my 7.9G Fluval Flora tank in the other thread, but you can see for yourself. This line has been bred together (red and black) for at least 2 years by someone else, then by me for another 3.5 years. I don't see any trend of colour fading or changing so far.

 

And although I have so many different lines of PRLs, this line of regular CRS is not something I would give up, they are the most toughest and prolific CRS/CBS I have seen. This tank is in the living room, it can get to 28-29 degree C (~80F) in the summer, and 17-18 degree C (low 60F) in the winter, no issue at all. So far this year, I've only done ONE 15% water change, and top off as needed. Substrate is 2 years old ADA, and breeding simply never stops.

 

[JamesHe]

Ok, I have something to say about it.

 

in short, it depends on your bee shrimp source (or gene).

[JamesHe]

In Breeders&Keepers Vol 2.

 

It describes it as Dominant-Recessive inheritance and intermediary inheritance/Co_Dominant inheritance. (pg 25)

 

I think you have the first case.

[randy]

I talked to someone with a PhD in genetics today, she doesn't think one animal can have both Dominance/Recessive and Incomplete Dominance if the phenotype is decided by one gene. (**But I have something to add to that later on.)

 

Note that co dominance is a bit different from incomplete dominance. The former on bee shrimps would result in a shrimp with both red and black as both red and black can be dominant. It's a bit uncommon but not super rare. If you look at that picture I posted above, you can find at least one. Incomplete would be red and black yield a different colour in between, example is that red flower x white flower yields pink flower.

 

** What I want to add is, the colour we see on shrimps is not a single genetic feature. There are many layers that consist of shrimps shell, the colour is the combining result of several layers.The colour we see would be the result of several genetic features combined together, each controlled by a gene. So, it could still be simple dominance/recessive on each layer, or a mix of dominance/recessive and co dominance on difference layers, even incomplete on some layers too.

 

Now, it's too complicated and I took my genetics more than 20 years ago. What I tend to believe is that it is simple dominance/recessive, so all my shrimps are still either CRS or CBS. As to why we see some CBS that looks more like brownish than black? I think that's just the quality of the black colour. Just like in CRS, you can have some with bad red colour that it almost looks like pink or orange.  Another proof is that, I have a line of pure line CBS, I have not seen one CRS from that tank, however I do still see some with not so good black (culled, of course). So if that's what people think as the incomplete dominance then it doesn't make sense as my pure line has no red gene?

 

We're all guessing with the observation of the phenotypes we can see, genetics is not an easy topic, I'm just expressing what I believe based on what I have observed. Maybe some day I will change my opinion, but for now, I still tend to believe it's just dominance/recessive. Thanks James for bringing up the point for discussion. I have that magazine but I can't remember where I placed it, I'll try to find it and see what the breeder says.

[Soothing Shrimp]

Excellent write up Randy!

[JamesHe]

I saw brown shrimp as a result of mixing CRS and CBS. this is the co-dominant inheritance case I believe.

 

[randy]

Thanks James for the picture. That probably is a proof of the shrimps colour is determined by multiple layers and each layer has a different gene controlling.

[Soothing Shrimp]

If the Chocolate is caused by a poor layer of black, I wonder if it is even possible to get a solid color of chocolate or not.

[JamesHe]

Thanks James for the picture. That probably is a proof of the shrimps colour is determined by multiple layers and each layer has a different gene controlling.

 

You can spot couple very nice pure black and pure red peewees, and parents are more looking like brown color.

[woopderson]

This is something that I was wondering as well.  My CRS haven't thrown anything other than more CRS. No goldens, even.  I purchased these from Randy back in May. If I put CBS in there now, what exactly will happen?  Will the red genes dominate and the black disappear? What are your thoughts?

 

I had also held off as people were saying I would end up with brown shrimps.

[randy]

This is something that I was wondering as well.  My CRS haven't thrown anything other than more CRS. No goldens, even.  I purchased these from Randy back in May. If I put CBS in there now, what exactly will happen?  Will the red genes dominate and the black disappear? What are your thoughts?

 

I had also held off as people were saying I would end up with brown shrimps.

 

Darn, you got the cheapest PRL available then ;-)

 

Based on the info that's available now, it depends. I've done this many times and haven't not noticed the brown ones. And I doubt many of our CRS haven't had CBS in the pedigree, so I think the chance of getting brown ones is small, it's your call. If you're getting no golden in the offspring (I know you have had many many babies by now), then I would recommend not to mix them with anything else. The colour on your shrimps is pretty good and you can keep working on them to get your own PRL, just need more observation.... I do put my PRL culls in the regular CRS tanks.

[Soothing Shrimp]

There is some theory that red is recessive to black, however I have heard of people getting black thrown in a red tank.  Go figure.

[woopderson]

My guess is the colony is easily over 150 from a start of 18 shrimp. I feel that that much production and not having any one-offs is pretty good. I will take your advice and keep the line pure. Perhaps eventually selling the culls.

 

Looks like I may consider a CBS tank of its own once I have a place to put in a shrimp rack

 

 

Darn, you got the cheapest PRL available then ;-)

 

Based on the info that's available now, it depends. I've done this many times and haven't not noticed the brown ones. And I doubt many of our CRS haven't had CBS in the pedigree, so I think the chance of getting brown ones is small, it's your call. If you're getting no golden in the offspring (I know you have had many many babies by now), then I would recommend not to mix them with anything else. The colour on your shrimps is pretty good and you can keep working on them to get your own PRL,

just need more observation.... I do put my PRL culls in the regular CRS tanks.