RE: how do you call...

["David A. Youngker" <nestor10@mindspring.com>]

  -----Original Message-----
  From: JerrCarol@aol.com
  Sent: Friday, May 17, 2002 4:26 PM


   > ...The question as I saw it was if you bred a Wild fish to a captive
  > bred fish. What would it be as far as the F system is concerned?
  > My logic would say you have a wild fish being bred for the first time
  > to another fish regardless of whether or not the other fish is wild it
  > would be the first generation of those fish being bred in captivity. ..

  First off, as has been mentioned, there is _no_ "F0" generation - it's
known as the "Parental" generation, or simply "P". Offspring from P = F1,
the first "filial" generation. Filial is from the Latin filialis, meaning
"of a son or daughter".

  The filial progression normally considers the offspring of each
_distinctive_ generation, created by the free intermingling and mating of
the generation in question to produce the next. Two notable exceptions to
this scheme, documented in most genetic manuals, are "Test" crosses and
"Back-" crosses. I'd guess that most of us are familiar with the term
backcross - a test cross is merely a version of the backcross with the
specific goal of testing for a homozygous individual as opposed to a
monozygote. At any rate, a backcross mates one of the progeny with a member
of its parental line - or one with an identical genetype to the parent.

  Since the normal course of line breeding crosses the original parental
genotype to one of the filial generations, and the "P" is understood, the
usual notation is "Fx backcross". Most breeders wait until at least the
second or third generation to perform the backcross (as the extra generation
helps localize the desired trait just a bit more), so you usually see
something like "F2 backcross" or "F3 backcross". However, if you backcross
short of the Parental, then you should denote the generations involved
similar to the "hybrid" notation - as in "F2xF4 backcross".

  When test crossing, the offspring are usually referred to as simply the
"test cross progeny". In the case of line breeding, the backcross also
establishes the predictability of passing the trait as well as reinforcing
the genotype, and these often become the new Parental generation for your
"established" breeding line.

  It's been mentioned that the terms "wild caught" and "captive bred" have
no bearing on the filial notation, which is true. WE, as Apistophiles, have
merely chosen to use "wild caught" as the _convention_ for the "P"
generation, as well as settling on "F0" for the same. That's like the
on-going arguements over terms like "carbonate hardness" and "alkalinity" to
describe acid binding capacity.

  Now, of course, comes the "kicker". What do you call the offspring of WC
and CB?

  That depends on the _goal_ of your breeding efforts. Are you trying to
breed traits from the wild-caught into the captive breds, or vice-versa?
Will you backcross to one or the other as the "Parental" generation?

  Does it really matter in the long run? After all, if you bred them in your
_tank_ rather than their natural environment, isn't everything you _produce_
"captive bred"?...

  -Y-

  David A. Youngker
  nestor10@mindspring.com




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