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Re: species maintenance (genetic thoughts)
KI>Actually, we probably wouldn't need a database, just a species exchange
KI>listing section of the FEL, I'd think. Those who are keeping a particular
KI>species list what they need new stock for and exchange with whoever
KI>answers. Certainly this could be quite well encouraged.
Good idea. I guess I couldn't see the forest for the trees....
That having been
KI>said, though, I'm not sure what it'd get us. As I understand it most
KI>collections consist of a fairly small number of fish (not more than 10?)
KI>from which all populations of that collection code are descended. This
KI>makes for a pretty serious bottleneck, and a few generations of inbreeding
KI>among relatives should lead to most population strains being pretty inbred
KI>at this point. A bunch of the genetic diversity in that initial collection
KI>would be lost quickly unless the number of keepers of a species is growing
KI>exponentially.
Yes, there's a pretty good bottleneck there, but what about
randomization during meiosis? Would that reduce the degree of similarity
among individuals and family lines?
KI>Fish that are poor doers cull themselves.
Unless the "hand of God" (ie the aquarist) intervenes.
However, they may also carry
KI>beneficial alleles as well, so by operating under a stingent culling
KI>regime, we are effectively reducing the genetic diversity that much more
KI>severly each generation.
I hadn't though of that. Good point. I was looking strictly at the
phenotype rather than genotype. Oops.
This isn't to advocate breeding "duds", but,
KI>well, no, actually I think it *is* to advocate breeding duds, particularly
KI>of species where the original populations are endangered. To maintain as
KI>much diversity as possible, you'd want to have every fish contribute
KI>equally to subsequent generations (impossible). By reducing the number of
parents who give rise to each successive generation we increase the chance that
beneficial (but
KI>silent) genes are lost.
Perhaps an approach might be to maintain separate family lines of "good"
and "dud" (whatever those terms might mean) and do periodic back and
outcrosses? Plus regular additions of fish from other lines (ie other
aquarists)? Justsome ideas, don't know how viable they might be.
For example, any traits that may assist in
KI>predator evasion are irrelevant in our tanks, and so may get lost.
Unless we keep them with pike cichlid or some other large piscivore
(grin)....
KI>It seems that the aims of keeping fish and maintaining genetically diverse
KI>species don't always line up exactly. I think that in the interests of
KI>both though we could:
KI>1) do more fish exchanges
KI>2) not cull too stringently. This may lead to more dull fish, but if there
KI>are thoughts of reintroducing fish from these extraordinarily maintained
KI>resource it might be worthwhile for some to dedicate some space to
KI>maintaining less desirable fish, too.
KI> As a newbie killie keeper, but a population geneticist I'm struck
KI>with the amazing efforts to maintain these species. If you were to set out
KI>to design a system for maintaining genetic reserves using a diffuse set up,
KI>I think what we have is pretty much what you'd aim for. From a scientific
KI>standpoint it strikes me a bit like the biological equivalent of
KI>SETI-at-home. It occurs to me that one could probably maintain a lot of
KI>plant diversity by tapping into the networks of gardeners that already
KI>exist.
I'm also a seed saver, BTW (grin). You don't want to know what the
minimum number of corn plants needed to maintain a strain is....Makes
killie maintenance a whole lot easier by comparison (grin). I agree that
we already have the basics available to maintain diersity and
populations, the problem is making the best use of it. Maybe now that
more of us know about the KCC and Species Maintenance Committees we will
be able and willing to help.
Thanks Doug!
Catherine
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