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Basic discussion on genetics and its effects selective breeding of Dwarf Shrimp (Chris’s Research Part I)

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This post has been promoted to an article

 

Special thanks to Soothing Shrimp and Hungle64 for reviewing, editing, and suggestions on this article.

This is more or less a short write up to give you a basic understanding of how Dominant a Recessive genes work. This would help you possibly breed out a mutation (considering that is what most colors or traits come from), or understand how to cull out shrimp to get more consistent traits.

I wrote this so I can better understand the subject by putting it into my own words, but also to start documenting my research and things I have learned onto a single forum so others may interject to teach me more, or learn with me if you too are a newbie like me. Please take this writing as it is, such that I am not experience and my schooling is in Business and finance, not genetics or biophysics. I should not be taken as an expert in any form or way and just get my information from multiple resources which in return may be wrong as-well. Please double check all sources before taking it as fact.

Ok, first off we need to know the basis of gene before we can go into any discussion. Remember any living animals basically have 2 sets of each gene, one received by the father and one received by the mother. This combination of genes is what solely determines what physical traits the offspring display.

Genes are broken into more or less 2 types (more details and break downs to come), recessive and dominant. Recessive genes are the “weaker” genes and will be over shadowed by a dominant gene in the physical sense. But just because this trait is not apparent, does not mean it isn’t present in the genes.

To better understand this concept, you must first know what combinations can occur, and how they are physically represented. For the rest of this article let’s assume we are trying to breed a RECESSIVE GENE since this will happen more likely than not (a dominant gene “should” always breed out naturally because of evolution).

There are basically 3 types of gene combinations (Part II will build onto this)
1) Dominant/Dominant (D/D) – This shrimp will not display the trait, nor will it ever pass the gene down to any offspring. The best offspring you will ever get with this shrimp is a carrier, and only if breeding with a Recessive/Recessive, or a Carrier. Ideally when culling, these are the shrimp we are trying to cull, since they greatly reduce the number of shrimp showing the trait.

2) Dominant/Recessive (D/R & Carrier) – This shrimp will not display the trait, but have the possibility of passing this gene down to offspring. When this occurs we call it a “carrier” of the gene. This occurrence is also why many breeders suggest keeping multiple generations of offspring even if they don’t exactly show the trait you are breeding. If you cull these you are potentially removing more breeders of the trait, which also would offer more variances in the genetic pool (an opinion that is somewhat contested whether it effects how hardy the shrimp are or not).

3) Recessive/Recessive (R/R) – This shrimp will show the trait and is the goal you are working towards. In a normal world an R/R bread with a R/R will have all R/R babies. From what I have read this doesn’t always happen with shrimp, but more or less gives you the advantage, and the basic idea of your goal.

There is a somewhat simple way to figure out which shrimp you want to breed with which, I will give you a few examples of situations and what you could most likely expect in the offspring.

Both Parents are D/D
Dominant Gene Dominant Gene
Dominant Gene D/D – Doesn’t show or carry trait (Cull) D/D – Doesn’t show or carry trait (Cull)
Dominant Gene D/D – Doesn’t show or carry trait (Cull) D/D – Doesn’t show or carry trait (Cull)

One D/R Parent, and one D/D parent
Dominant Gene Recessive Gene
Dominant Gene D/D – Doesn’t show or carry trait (Cull) D/R – Carries trait, doesn’t show
Dominant Gene D/D – Doesn’t show or carry trait (Cull) D/R – Carries trait, doesn’t show

Both Parents are D/R
Dominant Gene Recessive Gene
Dominant Gene D/D – Doesn’t show or carry trait (Cull) D/R – Carries trait, doesn’t show
Recessive Gene D/R – Carries trait, doesn’t show R/R – Shows Trait (Goal)

Both Parents are R/R
Recessive Gene Recessive Gene
Recessive Gene R/R – Shows Trait (Goal) R/R – Shows Trait (Goal)
Recessive Gene R/R – Shows Trait (Goal) R/R – Shows Trait (Goal)

As you can see, this is why many breeders do not instantly sell culls after the first generation. This Generation, while not all exhibiting the trait, may be carriers. Selling carriers lessens the opportunity to have more breeders who birth more “trait showing shrimp”. In fact, many of the breeders I have read about keep up to 3 generations before selling the culls, this requires multiple tanks (Gen1, Gen2 Culls, Gen3 Culls, then a Selling tank), and requires moving juveniles to another tank with the possibility of losing them to acclimation problems. This is why you see multiple hobby breeders just have a trait tank and cull tank.

This is just a basic intro into what I am looking up and reading on. I do plan on adding more since this just scratches the surface of the basic information that is required before a more in-depth knowledge of selective breeding topics. I decided to start simple on my personal learning and go from there, and like I said, I might as-well type it up while I am doing it.

As per Soothing’s information, while this possibility works for CRS & TB shrimp, Neo’s tend to follow more confusing lines that deal with co-dependent genes (allele) and the bell curve. Part II I will talk about those instances in order to build on this some more.

Please feel free to comment in any way as this might help me figure out where to research and head next, or correct any misinformation I might have wrote. I will try to keep this first post updated with any edits and give credit where credit is due.
 

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Fantastic article, looking forward to the remaining parts.

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Great job!  I hope it is okay to expound a bit further on your article. :)

 

 

 

The common accepted theory is that the black is dominant over the red in CRS.  This is if we are dealing with homozygous backgrounds.

 

Homozygous means having identical pairs of genes for enough breedings.  You know that there is almost no chance of that particular shrimp throwing anything else but a phenotype (lookalike) of itself.

 

Creating a homozygous recessive (CRS) in theory is pretty easy- since the recessive is lowest on the totem pole, no other color should pop up.  HOWEVER, there are always surprises in backgrounds.  That is why breeders often do test breedings.  (Ie.  Testing a "Pure" red strain by crossing with a golden to see if any goldens are thrown.  If so, it has golden in the background close enough that it is not really Pure.)...or breed lines for several generations to make sure there are no "surprises" in the background.

 

So assuming the crossings are from "Pure" homozygous shrimp:

 

CBS x CRS = CBS

 

The CRS is now hidden in the background of the CBS offspring.  This is called heterozygous.  Or het for short.  The pheonotype, however, is CBS.

 

As mentioned above in the article: CBS (het CRS) x CBS (het CRS) = CBS + % CRS

 

---

 

TB, unfortunately, we really don't know too much about.  If there were just two colors, perhaps it would be more black and white. (Pun intended.)  But there's a lot more than that.  Often the punnet squares just don't work on TB.  Why?

 

Well, there's also the real life challenge of hierarchy of genes and recessive genes.  For example, let's say green was an actual color for crystals.  The hierarchy may look like Green > Black > Red

 

Black x Red = Black

Black x Green = Green

Red x Red = Red

Green x Red = Green

 

Now all these genes are involved and can throw Black, Red, or Green.  Trying to separate these out can be quite confusing with all the shrimp having different combinations of backgrounds and  throwing different types...  and this is just an example of 3 types of genes involved!...and just simple dominances and recessives!

 

I'm sure part two by 00camadro16 will discuss co-dominance and modifiers, which can be more confusing yet and applies often to TiBs and Neos as well as TBs!

 

Bravo on a job well done! :)

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Great thread guys, will put this to good use shortly, when my breeding project gets up and running!!!

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Great job!  I hope it is okay to expound a bit further on your article. :)

 

 

 

 

So assuming the crossings are from "Pure" homozygous shrimp:

 

CBS x CRS = CBS

 

The CRS is now hidden in the background of the CBS offspring.  This is called heterozygous.  Or het for short.  The pheonotype, however, is CBS.

 

As mentioned above in the article: CBS (het CRS) x CBS (het CRS) = CBS + % CRS

 

---

 

CBS(het CRS) x CBS(het CRS)= CBS(het CRS) + CBS+CRS

Result average based on lifespan would be

50% CBS(het crs)

25% CBS

25% CRS

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Yep.  I was going on phenotype to make it easier reading, but perhaps I should have carried it out more. :)

 

Thanks for elaborating. B)

CBS(het CRS) x CBS(het CRS)= CBS(het CRS) + CBS+CRS

Result average based on lifespan would be

50% CBS(het crs)

25% CBS

25% CRS

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Yep.  I was going on phenotype to make it easier reading, but perhaps I should have carried it out more. :)

 

Thanks for elaborating. B)

i was sure that you knew it. Just didn't want someone just starting out get confuse.

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Oh, and if you are figuring out notation for dominant and recessive, often we go capital letter and little letter.  Capital for dominant, little for recessive

 

Ie:

        B        r

 

B     BB     Br

 

r      Br      rr

 

 

 

BB = CBS (25%)

Br = CBS het red (50%)

rr = CRS (25%)

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Oh, and if you are figuring out notation for dominant and recessive, often we go capital letter and little letter. Capital for dominant, little for recessive

Ie:

B r

B BB Br

r Br rr

BB = CBS (25%)

Br = CBS het red (50%)

rr = CRS (25%)

Thank you, I have already started part II and Switching terms to stay consistent was getting annoying.

Sent from my SM-N900V using Tapatalk

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So I'm confused on this lol. Too much going.

But say you wanted a deeper darker black. If you can cross a Snow White in with crs CBS and tb to get a greater richer white enhanced, does it make sence that you can cross a bkk with a crs to achieve a richer black or a ruby or wine red to achieve a richer red?

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Would snow white be recessive then. Or golden be dominant. I've noticed a high percentage of golden in my tank. CRA CBS mischlings outnumber my goldens. But the percentile is about 75% goldens 10% CRS and 15% cbs

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Would snow white be recessive then. Or golden be dominant. I've noticed a high percentage of golden in my tank. CRA CBS mischlings outnumber my goldens. But the percentile is about 75% goldens 10% CRS and 15% cbs

I hope that my understanding to your questions is correct.

1. Snow white and Golden bee :

Snow white from a dominant genotype (CBS) and Golden bee from a recessive genotye (CRS).

2. I believe you said that CRS/CBS are outnumber the golden but the offsprings are :; 75% Golden/10% of CRS/ 15% of CBS, right?

It is possible that both CRS/CBS has golden gene.

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Yeah, I should have stated it this way. There is about 20-30 crystal reds and black in my tank. And about 10 of those have Snow White genes. The other 10-20 are mischlings and have wr rr bkk genes.

I also have 12 golden bee mischlings, which have bb gene. Keep in mind all of these are adults.

The percentages I was saying are the shrimplets in the tank.

Then of course I have 2 bb, two bkk, two shadows, and one wr. And tibees.

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"I also have 12 golden bee mischlings, which have bb gene."

 

Is this possible?  I thought goldens were recessive and won't carry TB. ?

Yes! When you cross TB to golden the F1 can have the phenotype of golden and genotype of TB.

Taiwan bees are recessive when compare to CRS/CBS.

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This whole discussion is mind boggling me. Lol.

I don't hope to achieve anything by the combination of shrimp in the tank. I'm letting it run rampid and breeding until something interesting pops up. Mainly because there is mischlings and tb I'm hoping to get more tb out of it, and that there is tib and there seemingly only breeding within tib maybe some pintos. Other wise it's just a tank to let run rampid until winter and start culling then.

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INteresting question though.  Is it better to have male TB x fem CRS misch, or fem TB x male CRS.  I would think the first one, but am I wrong?

You are right. I always seen male TB x female. Don''t know if it does make a different or not.

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