Conformation and Body Shape

[johnsmith]

Glad to contribute to the discussion Mike.

I was always blown away by the simple idea of isolated genetic potential as a vehicle for permanent change. I'm not sure the concept of evolution is quite accurate but certainly the concept of isolated genetic pools and change is.

It really comes down to this- if you isolate any population from the greater wild population you effect the entire population. Those individuals will create change within the limited gene pool that will make them permanently ‘different’ from the rest. IF you then reintroduce that isolated population back to the greater wild population, the entire gene pool will be permanently changed by the new genetic combination just introduced. You can, in effect, do what would take nature centuries to do - if at all, ever do. It is a profound impact. The result is nishikigoi.

Besides changes on ‘the outside’, there are also changes on the ‘inside’. Those two fish pictured, for instance, have a different swim bladder configuration. They also have different length guts. Different serum blood levels, different storage concentrations within certain cells and different vitamin needs/storage and usage.

The scientists will continue to debate environmental change vs. genetic imperatives. But for us, nishikigoi are definitely a unique race of common carp.

[PapaBear]

In a sense that is what we do on our very small scale. Changing gene pools by manipulating breeding patterns to achieve our own ends. What is curious to me is the different results one gets in species by breeding back within a family line.
In the beef cattle industry (odd connection but bear with me) breeding back closely within a family tree is avoided to prevent deformities (father/daughter pairings) and sterility (grandfather/granddaughter pairings). At the same time their are a very few who intentionally breed Grandfather to granddaughter to produce sterile offspring called "prime martins". They have all of the best physical traits of the genetic line thereby producing superior beef quality and growth while sacrificing the ability to reproduce those traits in future generations. (This practice is generally limited to pen raised baby beef and milk fed veal)
Fortunately for us Koi sterility issues haven't come into play with linebreeding, but the deformity rate is rather high at culling time which reveals the genetic weakness our manipulations inevitably cause. These issues make it just that much more important to introduce outside lines from time to time to keep enough genetic variety to keep from further weakening the genepools of our favorite lines.

[johnsmith]

That's true Larry. The only very bad gene I'm aware of in carp/koi is a lethal gene associated with certain wagoi/doitsu crosses. The normal 25% genetic phenotype expected doesn't happen cause the fry die!

As we've discussed on this board and over on NI many times, there is a rich background of outcrossing in koi- german carp, magoi, regional pools, local feral colored carp etc.

The famous Ichthyologist Eugene Bolan did some fabulous work on the tracking of gene pools in carp from their home waters in the Caspian sea to Europe and China in subsequent centuries. In that study, he used the Roman army and local 'fish farming' as both vectors and artifical 'isolators' of carp genetic material. Very interesting piece.
JR

[Sangreaal]

Quote: Originally Posted by MikeM These koi are taken from the Keirin Koi site. The Chagoi are 85cm and 83cm, respectively. The Gin Rin Ochiba is about 60cm (if I recall correctly). These are massive fish whose attraction is largely in the size itself. I think it instructive to compare the bodies of these three... any of which I would enjoy raising.

I put these three pics in widget form in order to compare the koi in a different way:

http://w83.photobucket.com/widgets/d...315/sangreaal/

This is my observation of the differences between the three--the chagoi is massive and powerful, in fact so musclebound-looking it lacks a certain grace. Note that the head seems a tad long and a little narrow--this follows through just behind the gill plates but starts plumping out behind the pectorals. The body behind the pecs appears thick and stiff. This would seem to limit the control the koi would have over lateral flexion.

The soragoi is not so massive but appears, to me, to be both graceful and powerful because of its balance. It has a nice wide head that flows right into the shoulders of the fish and its body streamlines nicely from nose to tail. There is no stiffness in this fish at all, and the conformation fairly screams power, agility and above all, grace.

The ochiba has the opposite problem to the chagoi--it starts out looking powerful with the promise of having control of the rest of its bulk (even though it is admittedly a little narrow behind the gill plates), but the tail tube lets it down miserably. Can a tail aparatus that much narrower than the middle of its body make long flowing powerful sweeps to propel it forward? To me, it looks like it would have to work that tail double-time to keep up with either the soragoi or the chagoi.

That's one of my pet peeves about ochibas in general. A lot of them have this type of tail tube and I'm wondering, could this be because of crossbreeding to a much smaller boned, streamlined patterned koi vs. the hunk and power of the chagoi or soragoi?

Marie