well, my point in that was that sometimes people need to out cross their lines and it would be convenient for them to get wild specimens if they didn't have other captive strains easily available to them or something like that.
also, who thinks that it would be a good idea for this board to build a directory of private breeders? _________________ New to fishkeeping? Click the banner
well, my point in that was that sometimes people need to out cross their lines
My point is that this was once thought to be necessary, when now there is strong evidence that says this is a counterproductive action.
Right now, there appears to be no reason to outcross to unrelated fish.
I realize that inbreeding depression exists, but you have to note that the effects of inbreeding does seem to be virtually negligible in most natural inbreeding populations. _________________ "Just don't look in my fish room honey... it's just better for all of us. "
Cichlids seem to be fine with inbreeding, perhaps because there is often fry predators when they are kept by hobbiests and not breeders, but guppies... especially the metallic ones look terrible! _________________ Fish, Volcanoes, and Photography PhotoBlog
line breeding often includes so many "breeding" errors that are expressed through inbreeding.
This is why it sure looks like inbreeding causes a problem.
Here's the dilema... if you inbreed, you express the problem. If you outcross and mask a problem, you could line bred to eliminate all the carriers of the negative allele, but how can you id the carriers... in fact, all you've suceeded in doing when you masked the allele was to spread it into the next generation, and the next and the next... _________________ "Just don't look in my fish room honey... it's just better for all of us. "
And MY point was for the invigoration of the gene pool. I don't believe in masking bad genes, but providing new and/or stronger genes that will keep the population connected to their wild counterparts. I'm not imagining something like dog breeding or guppy breeding here, looking for good appearance or a certain characteristic. Rather, it keeps the breeding more natural. Maybe that so-called bad gene is there for a reason, you know?
I dunno, it makes sense in my head. I can totally understand wanting to make a negative trait more noticeable in order to avoid it, but there could be plenty of new, positive traits in the wild that would make your captive population stronger. _________________ --Kathy--
outcrossing does not improve fitness of a captive population in the long run though...
You do mention the only valid reason for an outcross, and that is to obtain a new gene not present in a captive gene pool. However, you then blurred the line between what is a new gene and then implied getting a stronger version of some defective gene present...
Here's a valid out cross...
Captive Convict bloodlines don't have a very large humped head... some wild individuals are found with larger humps... we use those to obtain larger humps in our captive bloodlines.
Now here's a bad out cross plan...
Our convicts are having some fertility issues... numbers of fry produced are dropping down to about 20 per pair... we buy a wild caugt, mix it into our bloodline and now the fertility rate is back up to normal and we get larger batches.
Do you see the difference? _________________ "Just don't look in my fish room honey... it's just better for all of us. "
I'm not educated enough on the subject of wild caughts to take one side or the other. It does seem as if there an amount of pride in having them... I know I'm pretty pumped about the F1s I'm should be receiving soon. Personally, I'm happy they're F1s instead of F0s because I feel like they'll be happier in my tank not having experienced the great big lake.
For some reason talk of wild caughts from the ocean makes me think of "Finding Nemo."
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum