F1, f2, f3, f4..........

[merumontanus]

As I understand it...unless it's different for reptiles. The result of two non related animals mated together, their babies would be considered F1s. F2s would be that offspring of two siblings bred together or what is usually done is offspring bred to a parent. Keep up the inbreeding and the F number increase with each clutch. I was just wondering how far you can go before genetic defects become unacceptable?

Before you all get your pitch forks and torches out let me explain.

I'm well aware of the side effects from doing this. I also know why sometimes it's necessary. For what I'm wanting to do. This will provide the fastest most stable results.

Now, I need to ask this question because I've never bred reptiles. I've only ever bred fish. With fish as long as you start with an animal with a strong genetic background (little to no inbreeding in the line) you usually don't see defects until F3s, even then you can normally go to F6 before the losses outweigh the gains. I would only ever take it that far if what I was trying to bring out was being particularly difficult. I normally stop at F4 before adding non related genes to that gene pool.

So....how far can you go?

As Kent mentioned, F1 refers to the progeny of two, known, parental specimens; F2 to the progeny of two known F1 specimens, and so on. The first filial generation (and all the subsequent ones) does not make them what they are because they are related, but rather, because they are known to have been bred and born in captivity, and from parents that were bred and born in captivity as well, except, of course, for the Parental generation, which could have come from the wild but still had to have bred in captivity.

When we claim F1 specimens, it is not to say that the animals come from a related bloodline-- that is a complete misconception. In fact, it is entirely possible to have as many F generations as possible that are not related. Below you will find an example of this:

P= parental generation (unrelated wild caught animals)
F= filial generation (unrelated captive-bred animals)

As you can see, in order to obtain true filial (F) generations, it is merely necessary to have had the parental stock (PxP or PxF) bred in captivity-- any subsequent generation need NOT have been interbred between related specimens.

I hope this helps.

Cheers,

Fabián

P.S. Things get a bit complicated with ovoviviparous chameleons as there exists the possibility of sperm retention and other factors, but as mentioned, this is a gross simplification to address the erroneous notion of inbreeding.

 

[kinyonga]

What would happen if the pink circle was a WC male? What I'm asking is what would the blue circle ones then be? Back to F1 again?

 

[eisentrauti]

Yes. WC + Fx = F1

 

[drewtt]

What would happen if the pink circle was a WC male? What I'm asking is what would the blue circle ones then be? Back to F1 again?

I have googled this ad nauseum before, and have not come up with a concrete answer. I think that the trend would be to name any offspring of such a cross "WCxF1" or "F0xF1," adding a layer of complexity to the naming process. I do not know if this is the most appropriate protocol that the geneticists would learn in school, though.

Drew

 

[aeolis23]

With how many wild caught chams would you start (male/female)?
The next info comes out of my course about laboratory animal, it might be far from the answer you are looking for, but anyway, it might help.

***

The formula of Wright says that the increase of endogamy per generation (taking that you keep them all in the same enclosure, you don't add new blood and the animals randomly pare up) is :
F = (1/8 Nm + 1/8 Nf) . 100 %

With F being the fraction of genes that were heterozygous in the previous generation, are homozygous in the new generation.
Nm is the amount of males and Nf the amount of females.

The bigger the amount of males/females, the smaller the increase of endogamy, so the bigger the genetic variation you will maintain.

"Officially" (for laboratory mouse!) you can say a colony is genetic equal after at least 20 generations of brother-sister pairing up or kid-parent pairing up. Then F = 98,4%.

 

[jajeanpierre]

All these big time breeders on this site and no one has any thoughts?

Every single Thoroughbred racehorse in the world today traces back to only 3 foundation stallions from the 1700s--the Byerly Turk, the Godolphin Arabian and the Darley Arabian. Every one. The registry for Thoroughbreds has been closed for hundreds of years. I can't count the number of times Nasrullah appears in the first five generations of some of my horses' pedigrees and he was only born in 1940. They are all very healthy, successful Thoroughbred racehorses.

Defects only happen if there are hidden recessives that are more likely to be expressed with inbreeding. They are more likely to be expressed with inbreeding simply because if the gene is there and you are inbreeding, you are just increasing the chances of it showing up. There can be a loss of vigor when animals are inbred a lot.