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Lyarlla

Genetics

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Hi, just wondering, when it comes to genetics, which genetics are dominant and which are recessive? How do you bring out a recessive gene in future generations?

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Here are a few.

Dominant:

Red

Longfin

Singletail

Recessive:

Yellows

Orange

Melano

Black Lace

Shortfin/plakat

Doubletail*

Intermediary/partial Dominant:

Metallic

Dragon

The 3 irids - Turquoise & Steel, which when combined produce Royal Blue

Crowntail

*Doubletail, which often results in broad dorsals in heterozygous fish

Complex traits like Halfmoon result from multiple genes working together.

Dominant traits require the fish to carry at least 1 copy of that version of the gene.

Recessive traits require the fish to carry 2 copies of that version of the gene in order to show the trait.

Intermediary dominant traits are similar to recessive, except that when there is only one copy, the trait will be partially expressed.

Traits like HM are a combination of the 3.

To produce offspring with the trait you want, you need to use the right parent combinations. Bettas inherit 1 copy of the gene from each parent, to a maximum of 2 copies.

- For the offspring to fully express a recessive or intermediary dominant gene, they must inherit the same version of the gene from both parents.

- For the offspring to fully express a dominant gene they must inherit at least 1 copy of that version of the gene.

- For the offspring to partially express an intermediary dominant gene, they must inherit 1 copy of that version of the gene.

- For complex traits like HM, it's a mix of the above for each of the many genes involved.

Recessive and intermediary dominant genes will take 2 or more generations of line-breeding to be expressed if the initial cross did not result in the offspring inheriting the same version of the gene from both parents. Dominant genes will only take 1 generation to be expressed - if the fish doesn't show the dominant trait, then it doesn't carry it either.

I hope this was helpful.

To the mods: could my post please be made a sticky? :(

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So does this mean, for example, if I crossed a metallic plakat with a blue VT I would get metallic VTs? And if I crossed a metallic plakat with a red VT, Id be more likely to end up with red VTs than metallic ones? And if I then crossed their offspring, there is a good chance Id get some VTs and some plakats?

Just trying to get my head around it all :bighug:

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You can work out what you will get by using

punnett squares have a look

lots of fun working out what you may get, then seeing what you do get in a spawn its not always the same

Edited by jo oakley

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I should have said that different genes are usually not mutually exclusive. E.g. Metallic and red are not produced by different versions of the same gene, but are caused by different genes altogether, therefore they can be inherited together and separately.

Here are the phenotypes (appearances) that are caused by different versions of the same gene. 1 gene per line:

- Red, Non-red (yellow), Orange. I'm not a red expert so someone please correct me if I'm wrong.

- Metallic and nonmetallic

- Dragon and nondragon

- Melano and non-melano

- Black lace and non black lace

- Longfin and Shortfin

- Crowntail and nonCT

- Doubletail and nonDT

- More multi-factorial (multiple genes) traits like VT and HM play against each other - The combined gene versions of VT seem to be more dominant that those of HM

Homozygous Metallic x nonmetallic blue will produce fish that are heterozygous metallic blue. Search AAQ for more info about metallic genetics.

Metallic x red is like nonmetallic blue x red - you get bettas with varying degrees of both red and iridescence.

VT is longfin. Shortfin VT looks like Traditional PK. So VT x PK would produce VTs or VTs with somewhat better finnage if the PK is better quality, and they would carry shortfin. VT x HMPK is the same except the finnage might be even better because of the HM factors.

I hope this was clear :bighug:

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Thank you so much for your posts. You make a lot more sense than most of the websites I've come across! :) Yes it was clear. thanks. :)

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Glad to help :)

By the way, metallic and dragon are relatively new and weird colour types and although we roughly know their inheritance pattern, we don't know much else yet.

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Add cambo & blonde to the recessives and mask & opaque to the intermediates and maybe marble to a 'not particularly mendelian but heritable' category and we're getting closer :giggle:.

Edited by PeterJ

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Mendelian as in Gregor Mendel, who established the straightforward dominant v recessive pattern of inheritance.

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So non-mendelian is when there is an exception to the rule? ie, a trait that is often inherited but not necessarily so would not be plotable on a punnet square.

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Pretty much - though the mechanics vary a bit. Marbleing in the phenotype can skip generations so noone is really sure about how it is stored in the genotype. It is definately heritable (able to be inherited) as some lines throw marbles while others don't, but the punnet squares won't help you...

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