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a review of Mathematics of Evolution by Gert Korthof
10 Oct 1999 (updated 3 Dec 2004)
"The Darwinian theory is wrong and the continued adherence to it is an impediment to discovering the correct evolutionary theory"
|There isn't any outsider who penetrated so deep in population genetics as astronomer–mathematician Sir Fred Hoyle, with such a mathematical knowledge, with such an integrity to find out the truth, and without distorting his subject of investigation.|
Fred Hoyle was a lifelong Darwin, Darwinism and evolution critic. Every Darwin critic appears to know his famous Boeing-747 story to criticise the origin of life by pure chance. The story was much quoted, often without access to the original source. Mathematics of Evolution originally circulated as copies of a hand-written manuscript back in 1987, and has now for the first time been printed. This is fortunate because his Evolution from space (1981) and Why Neo-Darwinism Does Not Work (20) are out of print.|
Mathematics of Evolution contains a number of surprises: Hoyle's personal confessions in the introduction; his histone-4 case; his thorough analysis of the infamous Haldane's Dilemma. The main part of Mathematics of Evolution consists of his calculations of the core assertions of Neo-Darwinian population genetics. Even if all mathematics is skipped, the book is still worth reading. His 'Life from space' (Panspermia) hypothesis is present at the background and comes to the surface at a few places. Mathematics of Evolution, doesn't have religious overtones. Hoyle's attitude can be described as: "how far does the neo-Darwinian theory work?" with the real possibility that it does not work or only partially works. This is in great contrast to the standard evolution textbooks. If one adds the fact that Fred Hoyle is recognised in his own area mathematics, theoretical physics and astronomy, then it's clear that this book is an exciting event for evolutionists and Darwin-critics alike.
Hoyle's Panspermia theoryMathematics of Evolution does not contain an elaborated Panspermia theory. I found the following fragments:
Evaluation of the evidenceTo believe in extraterrestrial life somewhere in the universe is one thing. To believe that extraterrestrial life contributed in a substantial way to the origin and evolution of life on our own planet, is another thing. To believe that extraterrestrial life was the exclusive source of life on Earth, is an extraordinary claim. What kind of evidence could support such an extraordinary claim? Could there be direct or only circumstantial evidence? Circumstantial evidence could be some property or pattern of living organisms on Earth that could not be explained by neo-Darwinism. It could be only indirect evidence, because on its own it would not be enough. The properties should be linked with extraterrestrial origins. Direct evidence for example would be an organism recovered from a meteorite. However that would be mainly evidence for a possible transfer mechanism of life from space to Earth. The lifeform needs to be viable and able to multiply on Earth. All this has to be demonstrated. So far no analysable extraterrestrial lifeform has been found. The strong points of this book are not rigorous testing of a hypothesis against the biological facts. It's not the goal of Mathematics of Evolution. However to evaluate the panspermia theory, one cannot escape a full confrontation of Hoyle's theory with all the relevant biological facts. Irrespective of the conclusion that neo-Darwinism is wrong, Hoyle's theory needs positive evidence.
Evaluation of the panspermia theoryMultiple extraterrestrial genetic injections can only be successful if they all have the same genetic code. In the end this boils down to the requirement that all extraterrestrial input must have the same origin. What's the probability of this? A single input of genetic information could explain the appearance of life on Earth. And that means that our genetic code originated somewhere in space. The disadvantage of the single input hypothesis is that it leaves all further evolution of life to traditional Darwinian mechanisms of mutation and selection (18), which are insufficient according to Hoyle. Unless one claims that all genes were present in those first forms of life. Which is highly improbably because those first forms of life are too small to carry such a huge useless load (19). So both single and multiple invasions have their problems; the multiple invasions having the most serious problems.
Why is it a problem that the genetic code of the extraterrestrials and terrestrials should be the same? Is the code not necessarily derived from the laws of chemistry? No, it isn't! The genetic code is not a universal cosmic code. The problem with any theory that claims extraterrestrial genetic input, is that life on Earth is a closed genetic system. I strongly disagree with Hoyle's claim that "terrestrial biology is not a closed system". (p. 3) Why? All Life on earth happens to have the same genetic code. That would be no problem, if it would be the only possible genetic code available to life. Our genetic code is one of billions and billions of possible codes (1). The current one looks like a 'frozen accident'. The probability that the genetic code of extraterrestrial DNA is the same as the genetic code on earth, equals the chance that a Boeing-747 arises from a junk yard! It doesn't make a difference if foreign DNA should have exactly the same 3D-structure and the same 4 bases as DNA on Earth, because the problem is not in the structure of DNA itself. The problem is in the meaning of the sequences of bases, which is determined by the genetic code. Hoyle knows that the genetic code is conserved and redundant but apparently not that it is a 'frozen accident'. Nothing more than a highly arbitrary assignment of 20 amino acids to 64 base triplets. It does not help to send complete organisms with a built-in key to translate the DNA message either, because the only thing what will be achieved is a separate branch of life that will not mix with lifeforms on Earth. And it does not help to focus on the exceptions of the genetic code, if anybody would suggest that, because these are minor variations. And because they are minor, they are not too difficult to explain by evolution and so don't need extraterrestrial help. To circumvent the genetic code matching problem one could introduce extraterrestrial proteins directly into organisms. This will fail because there is no way to translate proteins back into the genome. It is forbidden by the so-called 'Central Dogma' (2). Hoyle's problem that extraterrestrial genes would at first not 'feel at home' on the Earth, is really an insignificant and small problem compared with the genetic code matching problem. If my analysis is correct, then there can be in principle no extraterrestrial input of genetic material into the Earth's gene pool. Diseases caused by extraterrestrial viruses is a highly improbable hypothesis for the same reason. Of course the genetic material of influenza viruses needs to have the same meaning as our own DNA to get the flu. Viruses depend on the machinery of the host cell. It's because the influenza virus and humans 'talk the same language', that we get sick (3). The point is: what is the probability that extraterrestrial viruses, if they exist, would have the same genetic code as humans? If extraterrestrial life is found, I would first have a look at its genetic code.
It is of not much help to go into historical questions of priority. Was Darwin the first to propose evolution by natural selection or had Blyth and Wallace priority? Blyth & Wallace were both evolutionists and had no idea of extraterrestrial origin of life as far as I know. Whatever the priority, it neither helps Hoyle's theory about extraterrestrial origin of life, nor does it help his criticism. These are disappointing, unnecessary pages. Hoyle goes on pointing to discontinuities in the fossil record just like creationists. He really claims that multiple bombardments of lifeforms from space explain discontinuities of life. He calls it 'the external incidence model' (p108). Hoyle invokes 'genetic storms' to explain for example the sudden appearance of different orders of mammals. 'Genetic storms' are 100% speculation and extraterrestrial events or viruses triggering genetic storms are 200% speculation. Uptake of extraterrestrial DNA is 300% speculation. 'Genetic storm', 'genetic explosion' (p108) are concepts which do not occur in biology, Hoyle treats them as facts! At the most they are metaphors. "Other species are highly sensitive to genetic invasion from outside' (p108): show me the evidence. This is a description in a new language, not an explanation based on verified facts.
Panspermia: conclusionWhen one combines (a) the perceived problems in the theory of evolution (Why Neo-Darwinism Does Not Work, 1982) and (b) observed signs of life in space (Life from Space,1981), then it is only logical to propose a Panspermia theory. I do not deny that there are unsolved problems in Evolution Theory. And it seems reasonable that raw organic material could come from space onto the Earth (4) and could have helped the origin of life. I also have no problem with the idea that the universe is 'biocentric', in the sense that the building blocks of life are widespread in the universe. However if Panspermia claims a substantial or even crucial contribution to the origin and/or evolution of life on earth, Hoyle needs criteria to discriminate between the extraterrestrial scenario and the spontaneous-origin-of-life-on-Earth scenario. What key observation would tell the difference? How could Hoyle tell the difference if he assumes that the genetic code of terrestrial life is the same as that in the rest of the universe?
How far does the neo-Darwinian theory work?The largest part of the book consists of calculations of the core claims of neo-Darwinism: evolution works by the selection of rare advantageous mutations. These are the questions traditionally answered by population genetics. Studying the textbooks (Fisher) he got mad and calculated it all from scratch! The questions he tries to answer:
Haldane's DilemmaHoyle's efforts to investigate the famous 'Haldane's Dilemma', also investigated by Walter Remine, results in the surprising conclusion that "Haldane's so-called cost principle is an illusion." (p. 123). And since Remine uses Haldane's dilemma as an important argument against neo-Darwinian evolution, Remine's argument is an illusion. Furthermore Motoo Kimura 'bases' his Neutral theory of molecular evolution on a wrong result of Haldane's calculation of the cost of substitution. According to Hoyle Kimura's calculations of high costs only apply to a continuing declining environment. Maybe this is the most sensational chapter in the book. Hoyle's worries about deleterious mutations in the human species proved prophetic. In January this year (1999) the geneticist James Crow (6) stated:
"3 new deleterious mutations per person per generation. Why aren't we extinct?"; "A way out is for mutations to be eliminated in bunches. This happens if selection operates such that individuals with the most mutations are preferentially eliminated".Hoyle's claims about the evolutionary benefits of sex are also confirmed by remarks of Crow:
"But such a process can only work in sexual species, where mutations are shuffled each generation by genetic recombination".
Protein evolutionHoyle has several objections to constructing protein phylogenies. The original situation of a protein is irrecoverable. The facts show "direct and obvious disproof of the whole concept of protein phylogenies" (p. 134). Hoyle does not give references or quotes, so it's impossible to check which scientist draws which conclusions from which data. I suspect that current textbooks are more careful and aware of pitfalls. He points out that the situation with DNA phylogenies looks better, but also has its pitfalls.
Deleterious mutationsHoyle devoted a chapter to the "Sociological Consequences of Deleterious Mutation Pressure" in which he describes how deleterious mutations accumulate in humans (he calls it 'genetic erosion'). Mutations accumulate if natural selection cannot eliminate them as fast as they are produced. But elimination of deleterious mutations means death or at least no reproduction. Hoyle is worried about the problem. In the last pages of his book he proposes what to do about it. However his proposal is impractical. Remarkably evolutionary biologists today are still wrestling with the problem of harmful mutations in humans. It's the theme of Mark Ridley's Mendel's Demon (10). Ridley also speculates about how to get rid of the excess of mutations. What Hoyle called 'genetic erosion' is now known as 'mutational meltdown'.
Mathematics of Evolution: ConclusionAmong the Darwin-critics Hoyle delivered a unique and mathematically underpinned criticism of neo-Darwinism. His own Panspermia theory is considerably weaker then neo-Darwinism, nevertheless functions as an alternative paradigm, which enables us to see old facts and problems from a new point of view. Strictly speaking his Panspermia and his criticism of neo-Darwinism are independent, but undoubtedly his belief in Panspermia reinforces his belief that the neo-Darwinian theory is wrong. Even if not all of his calculations turn out to be correct, Hoyle's conclusions point to possible weak spots and unfinished parts in the neo-Darwinian theory of evolution. Although negative, it is a useful reminder for evolutionary biologists. If Hoyle would have finished his book, he could have made an important contribution to evolutionary biology just like mathematical biologist and population geneticist Motoo Kimura.
Population genetics revisited18 Feb 2000
The science journal Nature published an important review of Mathematics of Evolution by John Maynard Smith (8). John Maynard Smith has been an authority in the field of evolutionary biology for decades. In the review he discusses "the cost of selection" (Haldane's dilemma) and the problem of non-functional intermediates.
natural selection won't climb the mountain, if there is no stepwise path up the mountainand that all genetic change has an advantage on its own. JMS does not mention any evidence for the last claim. On the contrary: he shifts the burden of proof to Hoyle:
Hoyle gives no reason why such intermediate steps could not have existed; it is merely an assertionHowever, Hoyle unquestionably gives a reason: histone-H4. Where are all the functional intermediates of histone-H4? JMS doesn't give evidence. At least he could have mentioned an unusual diversity in Histone H4 proteins in Tetrahymena (a single-celled eukaryote) which was already known in 1992 (15) and later publications in 1996 and 1998 (5). The combination of asserting that natural selection cannot jump over non-functional intermediates and the fact that JMS completely ignores the histone-H4 case is puzzling. If there is a protein which lacks functional intermediates (in eukaryotes), then surely histone H4 or H3 are good candidates. According to Graur & Li (2000) Histone H3 is one of the slowest 'evolving' proteins known: 'evolving' more than 1,000 times more slowly than the apolipoproteins. And as recently as January 2003 histone specialists G. Felsenfeld and M. Groudine conclude that "Core histones are among the most highly conserved eukaryotic proteins known" (16). JMS knows about histone-H4: Hoyle discussed it in his Mathematics of evolution and JMS mentions histone-H4 in his own Evolutionary Genetics. JMS is silent about an important problem even when Hoyle points it out to him.
Surprisingly the theory that natural selection cannot jump over non-functional intermediates causes as much trouble for neo-Darwinism (histone-H4) as for Hoyle's panspermia theory. The second assertion is masterfully pointed out by JMS:
"This is precisely the assumption he has rejected in order to conclude that intervention from outer space is needed."So there is a glaring inconsistency in Hoyle's panspermia theory. I think JMS is right here.
What should we conclude? A reasonable conclusion must be that Hoyle's panspermia theory has an internal inconsistency because of the rejection of non-functional intermediates while claiming at the same time that all costs are an illusion. Additionally that neither JMS nor anybody else did give evidence that natural selection is in fact capable of producing all the necessary intermediates of functional proteins such as histone-H3/H4. It is not clear what the relevance is of histone variants in a group of primitive eukaryotes (15) for the evolution of the histones of the higher eukaryotes with conserved histones. JMS concluded his review with the remark that it might have been better for the reputation of Hoyle if his book had not been published. How can others 'verify Hoyle's results', if the book had not been published?
Fred Hoyle died on 20 August 2001 at the age of 86.|
John Maddox: "Obituary: Fred Hoyle (1915-2001)", Nature 413, 270 (2001) 20 September.
An informative review of Hoyle's scientific career by an emeritus editor of Nature. Apart from Archaeopteryx, Maddox does not mention Hoyle's criticism of neo-Darwinism.
"Professor Sir Fred Hoyle [1915-2001]", Obituary by Chandra Wickramasinghe (Independent, 23 August 2001).
NotesI wish to thank the publisher, Brig Klyce, for all his efforts to get the manuscript published and so making it widely available for the first time and for sending me a review copy.
Brig Klyce also made a list of errata in the book.
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|Copyright © 1999 G.Korthof||First published: Oct 10 1999||update: 3 Dec 2004 F.R.: 20 may 2011|