Bt, Monarchs, and basic bio

[Martha V. Lutz & Charles T. Lutz]

Hello All . . .


Regarding concern that Bt corn may affect Monarch genetics, here's my $0.02
or so.

Anne Kilmer wrote:

"A friend of mine is carrying the flag in the battle for Butterflies
Against Bt Corn.
She is concerned, among other things, about the possibility of  genetic
damage among the Monarchs that survive their childhood sublethal dose of
Bt corn and survive to spread their tainted seed among the world's
Monarch gatherings in Mexico.
This seems to me a very unlikely problem,"


I agree that it is HIGHLY unlikely, for the following reason:  assuming
that by 'tainted seed' the writer means mutated gametes, the Bt toxin would
have to (1) be a mutagen, (2) affect germ plasm cells, not just somatic
cells, (3) cause sub-lethal but deleterious alterations in those gametes
that by chance alone were involved in a fertilization event, (4) cause
sub-lethal but deleterious characteristics in the zygote, that ultimately
affected important genetically-coded traits but NOT the Darwinian fitness
of the resulting individuals afflicted with the new mutations (i.e. these
new mutations would have to be perpetuated at least beyond one generation
to become significant at the population level).


A very rough and crude analogy would be for me to worry that because I ate
apple cores (yeah . . . seeds 'n' all) as a young teen, my gametes (eggs)
became 'tainted' (underwent deleterious mutations) and my offspring--who
are otherwise normal, healthy, and potentially fecund--will carry these
toxin-induced mutations and spread them to their children, etc.

Should I be worrying?  I haven't been!

I'm not even worried that the bit of skin cancer I had removed a year ago
affected my gametes.  Partly because after having five kids I am DONE, and
partly because the probability is vanishingly small that the natural but
dangerous radiation (from the sun) that caused the cellular changes
resulting in skin cancer also caused any changes that affected my gametes.
Actually, the damage that caused the skin cancer probably took place
decades ago, before I had my kids, but I am still not worried.  I didn't
sunbathe so extensively as to irradiate the relevant parts of my anatomy
with respect to producing gametes!  I doubt that my eggs were tainted by
the factors that caused skin cancer, and am not at all concerned that my
kids will get skin cancer FROM ME.  I do put sunscreen on them, however;
not to protect their future offspring, but to protect their somatic cells.
Important distinction!


Perhaps this topic relates to the 'genetic damage' someone mentioned, in
which Monarch larvae affected by Bt corn grew up to be adults with only
four legs . . .


In Stride,
Martha Rosett Lutz


Old lady sprinter in Iowa who has taught A LOT of basic bio to opaque
pre-meds . . .