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post #1 of (permalink) Old 01-16-2013, 12:00 AM Thread Starter
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Figuring out a fish's traits then Selectively Breeding

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... Male Parent B... Female

Name:  Black Guppy.jpg
Views: 3517
Size:  61.2 KB 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 Cherry Barbs Anyone?. 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!
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Last edited by ADJAquariums; 01-16-2013 at 07:02 PM. Reason: Fixing errors
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