What does F1 mean?

[winnalit]

Hey everyone just a quick question,

Seen a couple of ads around for Taiwan Bees and mischlings where they say F(number). Like F3, F4, F8 etc. 

 

What does this mean? Is it something to do with generations? What F are better?

 

If someone could explain it to me that would be great

 

Cheers!

[newbreed]

You're on to it! The F number is the generation.

F2 Mischling crossed with TB will provide hopefully TBM and any Mischlings will then become F3.

The number increases for every cross to a TB.

So the higher the number the more generations have been bred.

If you see a TB strain, e.g. BlueBolt F4, it referees to the fourth generation of pure BB x pure BB.

Hope that helps.

[jayc]

I'll expand on Newbreed's explanation above.

 

F1 stands for Filial 1 (or first filial). Filial is a word used to describe sons and daughters, and as Newbreed says it means the first generation from a genetic cross between parents.

For example, it can be used to describe fish that are first generation from wild parents (ie. the fry have come from wild caught fish), so it's seen as an indication of genetic quality.

Of course every generation of offspring is an F1. But you usually count at a defining moment in it's genetic cross.

 

So an F2 would be the 2nd generation from the original parents you are counting from.

An F3 would be the 3rd generation, 

etc.

 

There's also something called an F1 hybrid, which is the direct offspring from a genetic cross between parents, say a cross between a CRS and a Taiwan Bee. The term Mischling is used to describe this hybrid in the shrimp world.

The word "Mischling" is actually German for "Crossbreed".

When this crossbred mischling is crossed with another CRS, it's genetics are diluted, and you get a small % of Taiwan Bees.

When mischlings are crossed with another mischling it's genetics are even more diluted. And the % of TB are even smaller to the point of never getting a TB. It's like striking Lotto.

However, when you cross a mischling back with a Taiwan Bee, you get a larger % of TBs, but with the added benefit of strengthening it's gene pool when it's original parents where mixed with a CRS.

 

Another thing Filial numbers are used for is to determine how stable the genes are in a certain specimen.

For example, if you are looking for CRS, then an F8 CRS is going to be more desirable than an F1 CRS. 

The F8 CRS has more stable genes, than an F1 CRS which might have been an offspring from a mischling or taiwan bee shrimp.

Thus the F1 CRS is not as "pure" bred as an F8.

 

But on the other hand, it could also be an indication of how far it is from the desirable genetics. Like in the case of fish, an F1 Apistogramma or Discus might be more desirable than an F9 fish. Since the F1 offspring are direct descendants of wild caught fish. And if the breeding stock is small, and offsprings keep breeding with each other, then the F5 generation will have a very small gene pool diversity from it's original parents. <-- not good. Since it will be an increased risk of genetic defects/disorders.

 

Hope that helps fill in the gaps of the original question.

Edited June 24, 2014 by jayc

[CNgo2006]

Very nice explanation there jayc

[inverted]

Yes good explanation..... I knew about shrimp but its interesting the way it is applied to fish.

Thank You

[winnalit]

Wow very great write up guys. So many helpful people on this forum! thanks!

[OzShrimp]

F1 = swim as fast as a formula 1 car 😛

[JayMarshal]

That's the best way I have seen it explained, great write up!

[slin1977]

So an F2 would be the 2nd generation from the original parents you are counting from.

An F3 would be the 3rd generation,

I'll expand on Newbreed's explanation above.

F1 stands for Filial 1 (or first filial). Filial is a word used to describe sons and daughters, and as Newbreed says it means the first generation from a genetic cross between parents.

Just to make it clear....

F2 is really a mating between brother and sister F1

F3 is a mating between brother and sister F2

Because parent generation had 8 rounds of babies does not make it F8

Edited July 31, 2014 by slin1977

[slin1977]

Strategy for breeding desirable traits for instance TB phenotype would be to back cross the offspring to the parents thus aligning alleles into homozygous state.

The first cross of two unrelated phenotype would be heterozygous.

TB x CRS = 50 percent TB and 50 percent CRS

That is why almost most of them look nothing like the parents prob all CRS looking.

You might find a couple showing TB or a couple showing CRS phenotype.

You can continue breeding this F1 generation together and more than likely you will get more TB phenotype show up and more CRS show up than the first parent cross. This is due to the alleles pairing into homozygous state.

By choosing these offspring and back crossing to a parent or phenotype increases your chances a lot of getting the result you wish.

This cross brings the equation back to F1 generation.

However with more alleles of a desired trait to work with.

Anyone can say they are F3 /F4 but without following proper breeding technique and keeping accurate records it is pure random mating at the end of the day.

[slin1977]

Furthermore by line breeding down the generations of F2 F3 F4 each successive generation represents desirable traits that are kept, undesirable traits such as maturing too quickly in males, bad shape, poor colour etc etc are all weeded out by the knowledgeable breeder. Only the best get chosen for the next F generation. Thus the further you go down the track the purer the line gets.

[slin1977]

Now putting the F back into mishlings...

When mishling breeders say it is F7 or so on it means they have mated a TB into the mishling stock over seven generations. Each generation using a TB hopefully a different one each time.

[CNgo2006]

So an F2 would be the 2nd generation from the original parents you are counting from.

An F3 would be the 3rd generation,

CRS/CBS x TB = F1 Mischlings

F1 Mischling x TB = F2 Mischling

F2 Mischling x TB = F3 Mischling

And so on.....

[AllyL]

Question on this F1/F2 etc.

 

Are there any glaring differences (visually) on whether the shrimps are F2 or F7? 

Or do we just have to go by what the seller says?

[jayc]

I'd say it would be pretty difficult to tell just by looking at the shrimp.

[slin1977]

Question on this F1/F2 etc.

 

Are there any glaring differences (visually) on whether the shrimps are F2 or F7? 

Or do we just have to go by what the seller says?

They early F generations of a cross between tiger and CRS for instance don't show the recessive traits come through.

After F3/F4 they start looking like the original parents and a combination of them.

The same could be said for mishlings some look just like CRS / CBS and some look just like Taiwan bees.