[nafex] Re: So what is the point?

Steve N. Dulaney dulaney at wvi.com
Fri Jul 13 00:13:56 EDT 2001

Hello  the fluffy one,

fuwafuwausagi at muchomail.com wrote:

> Does anyone "in the know" care to offer commentary on the reality of
> genetic diversity in reference to Malus, Prunus, and Pyrus.   I understand
> in the case of Malus that there essentially is no diversity.

My first response is that I did not know that the molecular biologists had
already mapped the entire genome of the apple tree.  My second response it to
point out that there is essentially no diversity between the genomes of a
chimpanzee and that of a human, but I do not think that anyone would say
humans and chimps are the same.   I am not an expert on this material, but I
do follow it fairly closely.

> The modern disease resistance stemming from on crabapple, and the antiques
> basically so in bred that it is just random chance of the same genetic
> material.

If there is truly no genetic diversity between varieties of apples, then they
would all flower at about the same time, bear the same shape and color of
fruit, have the same growth patterns, etc. allowing only for soil and
cultural differences.  The fact that apples, and most other fruits, do not
come true from seed is evidence that there is indeed genetic diversity in
these varieties of plant.  The point is that "essentially the same" is not
"exactly the same" and neither you, nor I nor anyone else can predict which,
if any, of those few unique genes will be needed in the future.  I just think
that it is dumb to simply allow a variety to go extinct because it is
"essentially" the same genetically to another variety.

> This is a way of saying there is little value in preserving most of the
> stuff as it just doesn't have much genetic drift in the first place.

My reply:  See my argument above.  It does not take much genetic difference
(I do not think that drift is the term you mean here) to make a difference in
survivability.  Also, to use the human genome as an analogy, a surprisingly
large part of our identified genome appears to do nothing at all.  It is
apparently genetic "junk" to the best of our current understanding.  Why are
to genes still in our DNA?  Because at one time they were useful for some
condition.  That condition may arise again, and then those genes will switch
on again.  Even without knowing the genome of the apple, or any other fruit,
I predict that the same situation occurs in the genome of the apple tree.

> Besides does not our national germ plasm repositories know recognize and
> handle this type of thing.

National germplasm repositories do recognize and handle this sort of thing.
I applaud them for doing so.  However, I also know that those repositories
can only maintain collections so long as funding is available, and in this
day and age nobody can assured of perpetual funding.  Also I am the sort of
person who does not like to put all the eggs in one basket, thank you.

Steve Dulaney


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