Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Hardy–Weinberg Principle - Breeding
#1
I am hoping I can present some information without getting into an argument. Dart frog breeding is obviously based on what people are saying in preserving the genetic information of the wild populations. I want to present the information and some thoughts that may differ from this school of thought. Please, if you need to argue, just contain yourself. Questions are fine.

Hardy–Weinberg Principle - This concept is pretty simple. If you take a sample of a species, you can maintain the allelic frequency of that sample. It has one problem: to be 100% accurate, you need an infinite population. Random matings are unpredictable, and just like a 50/50 coin flip, sometimes a generation of frogs could face a 75/25 event. This would change the allelic frequency. If you had an infinite population, this would average out in time, hence H-W is valid. It is the violation of this need that can cause the error.

It has been argued that this genetic drift can be controlled. We will look at that later. But if that were 100% true, why do scientists have equations (Pearson's chi-squared test) for checking a populations deviation for H-W? Obviously, this error can be significant enough to need a measurement.

One can see a larger population helps. Sharing frogs across the hobby helps (but brings up other issues like disease). There are other ways to reduce errors. But, we can never lose sight of these errors.

The next part will be about acquiring some frogs and some issues that can cause more errors.
Reply
#2
The next big thing to keep in mind is sample size and make up. This GREATLY affects what genetic make up you are preserving. If the import is small, it may not have much diversity. Were 9 related froglets the only import (yes, this happens more than you know)? Were they from a small area of a wider range of interbreeding populations? Were they selected from isolated regions that normally don't interbreed? You don't know what the original import was; assuming it represents the majority of the diversity in the morph isn't necessarily accurate.

But, it gets worse. Where did YOU get YOUR frogs from? Do you know if they are siblings? Are they the same line you already have? How many are you able to keep?

All of these questions can be hard to answer. As you can see, you are not likely to be keeping a "snapshot" of the wild population as a whole. Again, you can only keep the diversity you started with.

That is the larger question. Are we maintaining a snapshot of what exists in the wild? The next is, do we have to?
Reply
#3
So, are we able to keep a captive population that matches the wild population as far as allele frequency? No, probably not. With so many unknowns, you probably now see how hard that would be. Bigger numbers can help, but not at the expense of good care. We are limited to what we can individually keep as pets.

Peoples' tastes come into play as well. Lets say certain RANDOMLY made matings produce frogs whose colors are less vibrant than others in your small population. Conventional random mating, H-W following people say this is best, its "natural", it is "conserving diversity". However, are you going to keep them all? Do you have room? If you need to sell them or even give them away, can you find people who want these dull representatives of their morph? My experience tells me that no, people will not want to have them. They will want the nicer specimens. So if you keep producing them, they are going to take up space or displace your own frogs. How is breeding these acceptable?

Some will say this is an extreme scenario. But is it? What if you have both brilliant and duller frogs of the same morph on your table. The first customer will buy the prettiest. And maybe, because there are no other left, someone else will buy the dull ones. Both breed them. Now you have one person selecting for brilliant color on purpose, another selecting for dull because thats what he bought. Isn't that what random mating was to avoid?
Reply
#4
Is H-W valuable? Sure. But the "random" mating isn't best. Take one example: random matings can cause inbreedings. We can select against them.

When you read about H-W, you always see the section on DEVIATIONS. This is the section we are probably most operating in. This is what one should keep in mind. And because of this, and other reasons, selection will trump random mating.
Reply
#5
Selection is the same as random mating where there are 50 people selecting frogs. Some may select hi blue, some hi yellow and as long as they are the healthy animals it shouldn't reduce much and it's just a random as any other method(as long as 1 person doesn't do all the selecting). If you bred unrelated and selected for hi yellow, which may happen in the wild, you'd have a healthy population. As Brian said the problems arise in breeding brother to sister and back to the parents. I think a program breeding unrelateds and being able to choose animals would lead to a much better acceptance of a breeding program. Just because you leave out runts and the frogs get bigger(to the point where you have to weigh them to see it) isn't a bad thing.
The arguments thrown out there are misleading. If you don't inbreed you don't get frankenfrogs. I think a selective registered breeding program would be a much better "step" for the hobby. Something where there is a "secretary" to help w/ entering frogs and an allowance of most frogs into the program. I'm not sure how true it is but I've heard of frogs that can't be traced to an import not being allowed. I've heard the current program didn't need "help". It seems that something a little more inclusive may do a lot better w/ recruitment. Not that I have a horse in the race anymore it just frustrates me to see the attitudes and followers cutting down people when they don't even know what they're fighting for(labeling inbred fish as to what would result w/ darts, let me tell you people most are already inbred to the same degree).
Just some thoughts.
"I don't want to believe, I want to know" Carl Sagan(my fav. stonerSmile
Reply
#6
And Phil, thanks for allowing these conversations here. It seems that if you point out inconsistencies and question certain authorities on another board the conversation gets shutdown.
"I don't want to believe, I want to know" Carl Sagan(my fav. stonerSmile
Reply
#7
I agree 100%. I will add a bit: I am not against inbreeding IF done right. Basically, that would mean one inbreeding event setting a single trait (setting both recessive genes) like a color. Where you get into trouble is when you try to use a lot of inbreeding to make cookie cutter identical frogs and you don't take your time. Make your frog, breed it out and make as many carriers as possible. Breed more rr frogs. Lather rinse repeat. You will likely lose no significant genes that way (there are times you will have issues with this, but rare and not a game end-er).

I hope the attitude does change. As Aaron said, you can see on that other board how if you challenge the "experts" the try to get you banned for stuff that isn't even close to the crap they pull themselves. It is a clique, first and foremost. Not a group learning and growing, instead one trying to force its own inaccurate views across the hobby. I always say you have to watch out for close minded groups if you truly want to expand understanding.

If someone else proves you wrong, make sure they can't speak Wink
Reply




Users browsing this thread: 1 Guest(s)