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Thomas Jukes, "Some Comments
on the Newspaper Article "Scientists in War Over
"Neutral Theory of Genetics" by Deborah Blum,
Sacramento Bee, p. 1, March 16, 1992"
Unpublished Manuscript, March 19, 1992. |
SOME COMMENTS ON THE NEWSPAPER ARTICLE "SCIENTISTS IN WAR
OVER 'NEUTRAL THEORY OF GENETICS' BY DEBORAH BLUM, SACRAMENTO
BEE, P. 1, MARCH 16, 1992
About two weeks ago, I had a call from the author who had
been given my name by Will Provine. She said she had spent
two hours with John Gillespie in Davis, which is, of course,
the fortress of anti-neutralism started by Ledyard Stebbins,
who brought staunch anti-neutralists T. Dobzhansky and F.
Ayala to Davis. The tradition is maintained by Gillespie.
I chatted with Blum about the neutral theory and sent her
"Non-Darwinian Evolution," by King and Jukes (1969) and "Early
development of the neutral theory" (Perspectives in Biology
and Medicine, 34, 473-485:1991) by me. I see no indication
that she read either of them, but instead relied on phone
conversations, except for her visit to Gillespie, whose picture
is in the article.
The headline starts the article with an error. The neutral
theory is of (molecular) evolution, not genetics, but genetics
is an easier word to understand. As one should expect, the
motive for a reporter is to sell newspapers, not review science,
and the article is quite sensational. Here are some comments:
"researchers have started shouting at each other during cocktail
parties" Evidence?
"If Jukes and King began the fight in this country, the most
powerful proponent of the neutral theory on the international
scene was Matoo [sic]
Kimura, director of Japan's National Institute of Genetics.
Kimura began publishing on the theory in 1968. He has worked
tirelessly on its behalf since, and he considers it his own.
"I published one year before Jukes did," he said in a telephone
interview.
Comment: Science is international. The "fight" over our article
started in England (Clarke, Nature). Kimura may consider the
neutral theory "his own," but there are different opinions.
He did not publish "one year before Jukes did." I published
an outline in Molecules and Evolution (book) 1966. See my
review, cited above.
"In years John [Gillespie] almost single-handedly carried
the banner for natural selection" says Martin Kreitman.
Erroneous. Natural selection is accepted by all evolutionists,
including neutralists.
The theory predicts that genetic drift will occur at a steady
rate, so constant that by measuring DNA differences between
two species, one can calculate how long ago they separated
on the evolutionary tree. For instance, based on the tiny
variation between humans and chimpanzees, scientists believe
the two species separated about 5 million years ago.
That steady tick of variation is known as the "molecular
clock." ~
An excellent statement, but see the final paragraph, alleging
that I don't concede it. (wrong)
"But Gillespie says that new technology--allowing better
pictures of proteins and genetic material--has shown clearly
that the variation is not steady, that there are sudden rapid
bursts of change. The neutral theory fails to allow, as Gillespie
does in his work, for some real complications, such as a changing
environment.
Dick Holmquist and I were the first to draw attention to
the fact that variation is not steady. See "Evolutionary clock
nonconstancy of rate in different species" Science 177, 530
(1972).
"The people who introduced it have fallen in love with their
own beautiful math" Ayala said. "They've forgotten that it
isn't necessarily reality."
Ayala has forgotten that the neutral theory is based on reality,
not math. King and Jukes (1996) used no math. My 1966 outline
was based on the simplistic statement that "the changes produced
in proteins by mutations will in some cases destroy their
essential functions but in other cases the change allows the
protein molecule to continue to serve its purpose."
(Ayala) "The molecular clock concept should still hold. The
time spans . . . are so huge that a little wobble doesn't
mean that much." Neither Jukes nor Kimura concedes even that
much."
Incorrect. I have drawn attention to this point: J. Mol.
Evol. 20 87-98, 1987. I said, "The molecular evolutionary
clock tends to persist, despite great variations in its rate
of keeping time."
Summary: Gillespie emerges from this article as a hero who
has been mistreated by an intolerant and belligerent Kimura.
Kimura's hostility is said to be based on a cultural difference
("In Japanese society, that's very insulting"). The article
contains a number of errors, as listed above, some by its
author and others occurring in the quotations she has reported
in interviews. The people she interviewed, of course, may
have been misquoted. The concluding paragraph in King and
Jukes is recommended as an exposition of the neutral theory.
From these considerations it is not difficult to conclude
that the stream of spontaneous alterations in DNA, continuously
fed into the genetic pool, should include far more acceptable
changes that are neutral than changes that are adaptive. Protein
molecules are subjected to incessant probing as a result of
point mutation and other DNA alterations. The genome becomes
virtually saturated with such changes as are not thrown off
through natural selection. We conclude that most proteins
contain regions where substitutions of many amino acids can
be made without producing appreciable changes in protein function.
The principal evidence for this is the astounding variability
in primary structure of homologous proteins from various species,
and the rapid rate at which molecular changes accumulate in
evolution.
No mention is made in the article of James Crow, Noboru Sueoka,
and Ernst Freese, who helped found the neutral theory, although
this was explained in Jukes 1991).
THOMAS H. JUKES
March 19, 1992
This page was written by Michael Dietrich. It was last updated
on May 16, 2004.
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