>> Firstly, most mutations
>> are deleterious, and result in a plant inferior to its parents.
>
>This goes true for all mutations, also for those occurring in nature.
Yes, but nature deals in large numbers over long periods of time. Thus,
deleterious mutations are generally selected against, and neutral
mutations may be permitted.
>
>> Secondly, the rate of mutations is relatively low,
>
>Also in nature.
>
>> and therefore to increase
>> genetic diversity in cultivation would require eons, and a very large
>> population of plants, neither of which are likely in cultivation.
>
>Are they likely in nature for e.g., _Utricularia podadena_,
>_Nepenthes clipeata_, _N. campanulata_, etc.? Where? When? Do these
>plants have the potential to pass the test? I decidedly doubt that.
>
I am afraid I do not understand the questions at the end of this
paragraph, but I assume your point here is that these are plants that are
rare in nature, and therefore already possess little natural diversity. I
doubt cultivation is likely going to significantly increase their
genetic diversity. This is not really relevant to the discussion of
whether we can reproduce and preserve the diversity in cultivation found
in the wild for most species, which occur (or at least have in the past)
at many sites. Perhaps the diversity of extremely rare plants can be
preserved in cultivation, but in general this will not be possible for most.
>The important difference between nature and cultivation is, and here
>I wholeheartedly agree with you, in the quality of the selective
>pressure. There is diversity and evolution in cultivation and
>there is diversity and evolution in nature but the diversity in
>cultivation does not serve the adaptation at natural habitats (but at
>those in cultivation). It is my point to show that science alone
>cannot serve to provide arguments for or against cp cultivation or cp
>collection. Therefore I wrote that first there must be agreement
>among all human beings that we all want to preserve *natural
>diversity*. I cannot see this kind of agreement at the moment (but
>rather that everyone wants to get as many bucks in as short a period
>of time as possible), so science is rather hopeless in this kind of
>discussion.
We agree here, except that I donUt feel that cultivation contributes
significantly to species diversity. The numbers of individuals cultivated
are just too small.
>I do not know why you think so (if you refer to the differences
>alone, not the quality of these differences). It is possible to grow
>e.g. the different subspp. of _Pinguicula longifolia_ all in one
>setup. In some taxa (_Drosera aliciae_ s.lat., _Pinguicula
>moranensis_ s.lat.) the differences between the plants in cultivation
>very well compete those found in nature. Some of their mutual
>offspring literally swamp some collections. _Nepenthes_ hybrids come
>in nearly all shapes possible and spoil some of the finest
>collections with indeterminable rubbish (however, the diversity is
>immense).
Part of our disagreement here is in the definition of diversity. While it
iss true that a hybrid represents greater genetic diversity than one of
its parents, because it contains genetic material from parents from at
least two different species, it is not useful in terms of conservation of
species. It is diversity within a species that is relevant in terms of
conservation. I am refering to differences alone, and not the quality of
the differences. When I say the genetic differences between individuals
from isolated populations can be huge, I am refering to what I know of
the small nematode I work with, Caenorhabditis elegans. Often, in
attempting to clone genes one identified RFLPs, which are just detectable
differences between individuals. The number of RFLPs one can identify
between two individuals within a single species is huge. Probably on the
order of tens of thousands or more. This suggests that if one were to
determine the complete DNA sequence of representatives from two different
populations, one would find very large differences even though they are
in the same species. This is what I refer to when I speak of genetic
diversity. Whether or not most of these differences are important, who
can say?
>
>> Agreed. I think education is very important. However, it only takes a
>> single unscrupulous individual to destroy sites in the wild.
Therefore, I
>> still feel that one must be very careful in releasing detailed locale
>> data to strangers.
>
>Who are the strangers? You should not help a killer. But do you know
>who will be the killer within our population? I guess this is one of
>the drawbacks of our own diversity (not necessarily only genetic). In
>any event it is rather strange to suppose that scientists are always
>harmless and amateurs are always dangerous. As you said already, it
>only takes a single unscrupulous individual (thanks for not having
>specified that individual's profession here)...
I purposely did not specify any profession here. My main point in this
and my previous posts on this topic is that we need to do all we can to
protect habitat whenever possible. Because it only takes a single person
to destroy a site, I am very concerned about proposals to make detailed
information on rare plant locations to anyone with a computer. I am
making no distinction between scientists or anyone else. When I see film
of a scientist killing rare animals so he or she can study them, I am
just as disgusted as when I see some greedy collector harvesting plants
or animals for profit.
Wayne Forrester