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-   -   Figuring out a fish's traits then Selectively Breeding (http://www.plantedtank.net/forums/showthread.php?t=214906)

ADJAquariums 01-16-2013 01:00 AM

Figuring out a fish's traits then Selectively Breeding
 
2 Attachment(s)
Hello Everyone, this is a question i don't usually see a ton but when it comes up it seems like no one gives a complete answer, me included, so i figured i'd help with that in one thread. This thread will be on figuring out fish's traits using Mendelian Genetic's. But before i begin there are some key terms that need to be known...

Allele- Different Version's of a gene, they will be shown with letters, ex.) Aa

Dominant- An Allele that will always affect an organism's traits if present

Recessive- Only affects the organism's traits if in a pair, ex.) aa

Homozygous- 2 of the same Alleles

Heterozygous- 2 different Alleles

Genotype- The genetic make up of an organism, Ex.) Aa

Phenotype- The Physical appearence caused by the Alleles. Ex.) Widow's Peak

Ok, so now all the Vocab is done let's get to the good Part...

Figuring out an offspring's traits

To figure out an offspring's traits, first you need to observe the parents...

Parent A... Malehttp://www.mslivebearers.com/sitebui...s/snc12669.jpg Parent B... Female

Attachment 67442 Lets now say that male is Heterozygous for the color Allele, as well as the Female. so that would create a ratio that would look like this...

1:2:1 (Homozygous Dominant: Heterozygous: Homozygous recessive)

Lets now say the Homozygous recessive is the fish's offspring that yeilds a blue color, There would be about a 25% Chance of the offspring being blue, however this is a chance, so it may or may not be the way it happens. If you want to continue the blue trait in the offspring then you would want to breed 2 of the Homozygous recessive fish to give you a 100% chance of the entire next batch of fry to have the blue trait. However this could take several "experimental" groups, because being there only a 25% chance of getting the trait the offspring may not always have the desired Phenotype

What this means to you

By figuring out atleast some of this then you can know which fish to breed in order to have that specific trait. A lot of people know this as Selective Breeding, which it infact would be. This can be done to get traits such as longer fins, color, and patterns. Some of these traits can help bring in some good old $$$$, ecspecially if they are desired. I know of someone who is doing this with their Cherry barbs, it just so happens to be msjinkzd http://www.plantedtank.net/forums/sh...=199765&page=3. msjinkzd has bred these cherry barbs to be redder and have longer fins, both of these traits are because of genes and recessive and dominant Alleles, and over time msjink has been able to figure out which ones to breed to get that trait. This has created a Cherry barb with very desireable traits that could and is desired, hint hint, wink wink ;). To continue to breed these cherry barbs to have these desired traits a female with the traits as well as a male would have to be bred, in this case the female wouldnt carry the Allele for a red color, so the male would need to carry either a Heterozygous or a Homozygous Dominant Allele for the Red Trait.

How to get these fish to want to breed

To get these fish with desireable traits to breed you obviously need them to be of the opposite Sex. With fish such as Cherry Barbs it is as easy as sticking the Opposite sex fish with the other with the desirable trait. With fish such as Angelfish and Rams that pair up it may be a bit more difficult to do, i can't help there.

Why does this one look different?

A fish in a batch of fry will sometimes look different. This is because of a Mutation. A mutation can occur to give the fish an advantage to survival or it can hinder a fish's ability to live. This is seen a lot in Evolution, ecspecially with animals. This is really seen the most in sea dwelling mammals such as Whales and Doplhins. They are believed to be descendents from land dwelling creatures that slowly lost it's land based legs in exchange for fins to swim. In this case it is a distinct advantage to the creature because it helps it survive in an aquatic environment.

Disclaimer: I have the knowledge base of a 10th grade Advanced Biology student so some of the information given in this thread may or may not coencide with the facts or some silly error could have been made (if one is found please let me know in a polite manner, i will fix it!), even though everything given in this thread has been taught to me by several teachers and even a college professor, however the professor dumbed it down a great deal in order for us to understand. I have attempted to create this thread in an easy to understnad way to try and increase knowledge about this topic. If you have anything you would like added PM me or add it as a response and ill be sure to get it in here. (The attatched image has nothing to do with the thread, it can be ignored, i had to change out the pictures)

Thanks for reading!

ngrubich 01-16-2013 03:00 AM

For the blue offspring example, you would "expect" to observe ~25% of the offspring to be blue (1/4 of the punnett square would be homozygous recessive bb) the other 75% is a mix of genotypes (50% heterozygous and 25% homozygous dominant), but will still give you the normal phenotype. To avoid confusion, I would probably put pictures of the parent being plain-colored, and the offspring blue (the way you have the pictures and wording presently implies that heterozygosity gives you the desired phenotype).

This is a great little "crash course" in Mendelian Genetics, though!:proud:

ADJAquariums 01-16-2013 07:55 PM

Quote:

Originally Posted by ngrubich (Post 2254754)
For the blue offspring example, you would "expect" to observe ~25% of the offspring to be blue (1/4 of the punnett square would be homozygous recessive bb) the other 75% is a mix of genotypes (50% heterozygous and 25% homozygous dominant), but will still give you the normal phenotype. To avoid confusion, I would probably put pictures of the parent being plain-colored, and the offspring blue (the way you have the pictures and wording presently implies that heterozygosity gives you the desired phenotype).

This is a great little "crash course" in Mendelian Genetics, though!:proud:

Thanks for the tip! I will definatley fix my wording there.

papwalker 02-25-2013 04:55 PM

... or you could set up a lab, Grab a copy of Ugene
http://ugene.unipro.ru/download.html
Scour the gene bank and libraries to get your sequences then get a cycler and sequencer from [Ebay Link Removed]
Then get into plasmids and start churning out frankenfish.
Be the new Craig Venter (with more hair) or Glofish

:red_mouth:red_mouth:red_mouth:red_mouth:red_mouth

AquaStudent 03-25-2013 12:09 AM

Awesome write-up :D This brings me back to when I took biology...before my physics days

I feel like the trickiest part is determining which genes are recessive vs. dominant. Well trickiest as in without experimentation. Do you know of any databases that have traits categorized and labeled for different species? I'm sure bettas and livebearers would be a fairly common topic.

wicca27 03-25-2013 01:10 AM

i know with guppies and the crosses i did japanese blue was domanite over snake skin, and even blue moscow body color. 2 years i have worked on a line and no other body color ever showed up but jape blue. also from working with them dad always seems to carry body color where as mom carries fin colors. but i have only worked on one line so far. i do have another guppy idea in the makeing but im sure it will take me several more years or alot of work before i can even start that one lol

papwalker 03-25-2013 03:48 AM

Quote:

Originally Posted by AquaStudent (Post 2929570)
Awesome write-up :D This brings me back to when I took biology...before my physics days

I feel like the trickiest part is determining which genes are recessive vs. dominant. Well trickiest as in without experimentation. Do you know of any databases that have traits categorized and labeled for different species? I'm sure bettas and livebearers would be a fairly common topic.

...and now we have epigenetics just to confuse things further. Lamarck would be happy.

Jeffww 03-25-2013 04:54 AM

Too bad color and patterning is pretty much multilocus. What we have now is pretty much the closest we're getting for awhile. Much of breeding is just the shotgun approach and then inbreeding until you get a pure line.


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