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The two most perplexing responses to my idea that lethal
juvenile cancer played an essential role in the origin and evolution of all
Bilaterians were from two respected scientists (one a biologist, the other,
not) and were very similar in their conclusion. A fair summary of both views might
read like this: “You are probably correct Mister Graham, but so what?”
Of course neither scientist used those words. The
non-biologist said he thought I was correct but that my idea was simply another way of
expressing Neo-Darwinism. The biologist, after stating no objection to my
theory, said that I was wrong to consider it “radical.”
Perhaps the best place to begin considering whether or not
my idea is radical is with the following sentence from my 1984 Letter to the Journal of Theoretical Biology:
“Those [Bilaterian] germ lines that
created the most complex animals endured the most genetic losses to cancer and vice versa.”
I could have said the same thing less succinctly but more
emphatically:
Those Bilaterian germ lines that
“benefited” the most from intense selection pressure emanating from lethal
juvenile cancer produced the most complex animals. We humans, as (arguably) the
most complex of all Bilaterians, owe everything to this nightmarish
disease; without the death in our lineage of uncountable millions of young
animals we would not exist. Neither would civilization.
Let’s compare that statement to what the Index of the Second
Edition of Evolution by Douglas J.
Futuyma (apparently American universities’ most popular evolutionary biology textbook)
says about “cancer selection”: absolutely
nothing. Perhaps some reference to my
idea is buried in the text but I don’t have access to Professor Futuyma’s book
and with its listed retail price of $121.95 it will probably remain unread by
me. It is possible, of course, that
because of the limited attention it has received, my idea could have escaped
the notice of an author of an evolution textbook. Yes, that would be possible
for other authors but I know it is
not the case for Professor Futuyma who, while editor of the journal Evolution, read my manuscript proposing the theory and decided it was not worthy
of publication. (I thank him, belatedly, for providing the amusing epigraph to
Chapter Fourteen of Cancer Selection.)
COMPARING THE TWO
THEORIES
In summary, here’s my comparison of the two theories as they
relate to cancer and Bilaterian evolution:
Graham: Lethal juvenile cancer (cancer selection) played an absolutely
essential role in the origin and evolution of Bilaterians. If cancer did not
exist and had not actually killed uncountable millions of developing animals
none of the Bilaterians could have existed.
Neo-Darwinism: Cancer did not play any role in Bilaterian evolution. If cancer never existed
all animals could have come into existence in forms very similar to extant
animals. They might not have acquired certain anti-cancer characteristics but, although
such defenses might interest medically-oriented researchers, they are of no
interest whatsoever to theorists attempting to understand Bilaterian evolution.
The theories summarized in those statements cannot both be correct. One of them must be wrong
and I’m convinced it’s the widely-accepted conventional theory known as
Neo-Darwinism. In my next posting I will
propose a mental test that supports that view.
