I agree to that Aviculture should maintain a core of uncontaminated wild-type populations and that is a role for zoos or other interested individuals. Yes Myzo, ideally we should maintain large diverse populations but surely not for each mutant within a species? We don't have to be too precious about narrow genetics unless we are impatient - every inbred line can be outcrossed even "pure" wild-types as long as we're prepared to put the work in to bring them back to what we want. The current weakness of the blue Gouldian mutation is being addressed in just such a fashion as has every other recessive mutation. As for cold-hardyness in Gouldians, the point I was making was about the subjective value of what is considered desirable, natural and pure. Cold-hardyness or the lack there-of is certainly more than the absence of down feathers in Gouldians. While we can't see physiological traits in the same was as we can see a white breast they are there and have a genetic basis. If these variants are new we call them mutations if they are already established in a population we can call them alleles and will occur within populations at frequencies that reflect their adaptive value. It may well be that wild Gouldian populations brought into aviculture already contained a low level of cold-tolerance genes and that aviculturists have passively or actively selected to bring this trait from say 0.1% of the population to current level of 98%. The actual levels of expression of a trait in a population is as much of a concern as the origin of a "mutation" to some aviculturists who see any interference or deviation from the wild-type as unnatural and undesirable and to be avoided at all costs. If it's not obvious I disagree since nature itself is not static and gene frequencies ebb and flow to reflect changing environmental conditions and a captive population is hardly natural in the first place so why not have a population that is adapted to the reality of this situation rather than an unattainable "ideal" that reflects the conditions of a 1930s tropical savannah in northern Australia or Botswana or wherever the bird population came from?
I guess I have a "thing" about fundamentalist doctrines that can not demonstrate a rational basis for the premises upon which they are based whether it be religion, organic agriculture or for want of a better term naturculture (the belief that nature represents a static ideal and that this can be replicated and preserved in domestic culture). Just for the record I've never actively sought to keep mutations as I'm quite satisfied with what occurs naturally and am far too lazy to bother tracking mutations. Having worked in a genebank for the first half of my career I know just what an futile task it is trying to preserve all genotypes without knowing the actual genetic constitution of the stock and how easily cultivation can change gene frequencies when you try to maintain populations. This is not to say that genetic conservation is not important but we shouldn't believe that we can or should try to hold things in a completely static fashion especially in active (breeding) collections. Aviculture doesn't have the luxury of being able to freeze germ-lines like we do with crops but there are certain lessons to be learned about the nature of static gene-pools that we can learn from. While I was at the International Rice Research Institute researchers pulled some of the old varieties from the freezer which were the foundation of the green revolution and grew them out at the same sites using the same techniques as were used in the 1960s when there were developed. What they found was that their yield potential was 30% lower now than it was when they were developed. The environment of the 1960s was fundamentally different to that of the early 2000s and this static collection was no-longer adapted to the environment - the lesson here is that you have to change gene frequencies and bring in new alleles/mutations just to stay where you want to be. This is also known as the "Red-Queen" effect after the character in Luis Carol's Alice through the looking glass who had to keep running ever faster just to stay still.
Netsurfer I too believe that each species is an answer to a the problem of existence whose selection history took not just thousands but billions of years to come about and that we should respect that. However as I've just shown in rice, significant phenotypic shifts can occur in as little as 40 years without any change in genetics because the environment changes! In birds too is was shown in some of Darwin's finches during droughts that in a matter of 5-6 years that very significant shifts in beak size and shape occur as they adapt their diets and there is another study that shows that many bird species are currently getting smaller and that this is likely associated with climate change. (Sorry I can't look these up at present but my daughters seem to have used up this months 50 Gig allocation downloading One Direction videos and this has this limited my capacity and patience to search the net for references).Netsurfer wrote: GregH, sure but that happens over thousands of years and not virtually over night as it's happening in Aviculture. Who are we to interfere?
