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re: Cross-breeding Vs Inbreeding
Don't get mad at me!
A dog is a dog and a human is a human. Cross-breeding exists for the human
race and I think it gives
positive results. On the other hand, inbreeding brings more "problems" than
advantages. Dogs were cross-bred
for centuries to create what we now call "pure bred". To keep that pure bred
we have to inbreed them sometimes.
You end up with a pure bred with weak and strong points. Don't try to send a
poodle to the wild, but it will do fine
(?) in your house!
In my defenition cross-breeding is an unnatural form of making two different
species mate and produce fertile youngsters. Technically the crossing of
different type localitys of one species isn't crossbreeding, but on the other
hand they would never meet or breed under natural circumstances so I disagree
with this as well.
In this definition humans are not crossbreeding, because they make contact
with eachother themselves and chose to mate regardless of skin colour or
whatever. And that is good, because it's our own choice.
I believe dogs were not crossbred as well, but all come from the original
Canis canis (correct me if I'm wrong). The different races were made by
selective inbreeding, just like we did with the coral-platy. On the original
wild-caught platy there is one tiny red mark. Because we continually selected
out the individuals with the biggest marks we devellopped an entirely red
platy. This inbreeding will also result (as well as with fish as with dogs)
in other more "unpleasant" features, like missing gill-plates, anatomic
failures which are even worse than the red colour itself. Because I'm against
any form of unnatural breeding i don't like people to make red platys e.d. as
well, but you have every right to draw your own borders yourself.
Going back to fish ...
The biggest problem I see with keeping a "pure line" is that
the fertility goes down a lot after a few generation because of inbreeding.
How can you avoid inbreeding with a few couples of fish found in the wild 15
years ago? How do you keep them fertile for 15 years? Cross-breeding would
be a solution to bring "new blood" in the line (don't hit me!).
In Holland the KFN (Dutch Killiefish Association) has an very good
registration system. Fish that come in from the wild are registered with
their scientifical name + a code that tells exactly where they are caught. In
this system you can also reasd what member has what fish ( with code). In this
way people can exchange fish to keep the genetic diversity in one species.
Because the conditions are slightly different in every place, th fish will
also slighly differ from eachother, and crossing them back with eachother can
partly equal these differences.
When you need fresh blood from the wild you can also go back to the exact same
pool or creek to catch some more.
I have many question regarding classification of species:
1- The confusion between Aphyosemion and Fundulopanchax
I've read something about it in "Killies of the World" Volume 3 by R.
Wildekamp. I don't recall exactly, but I believe that it states that since
1981 some scientist has been trying to change Aphyosemion into Fundulopanchax.
It seems this name has now been generally accepted.
2- Why 2 genetically compatible species (or sub-species or whatever) are not
considered a unique fish with just different coloration ?
Scientists have been, and will be fighting over this for years. some see tons
of reasons to make something a new species, and others see none at all. The
definition of "species" appearantly gives room for this.
3- Is it possible that very similar species from close location in the wild
are the result of natural cross-breeding?
Yes, why not? That however doesn't mean we should do the same. Nature has the
resorces to select out the species that fit in the natural environment. I
don't think we can see clearly enough what's right and what's wrong.
4- What fish are considered to be part of the "Gardneri group" and why?
I have no idea at all, but I also wish to know
Hartelijke groeten van Jochem 't Hoen
jochem.thoen at 98_student.wau.nl
jochem at fgbbs_iaf.nl
no guts, no glory!
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