Could mutations be the reason for a new species?


The alteration that occurs on chromosomes and  the genes on the chromosomes is called “mutation”. Mutations, which might occur in natural circumstances, may also brought forth by means of artificial experiments. Chemicals, X rays and cosmic rays play a role in it. Mutations are divided into two sub-groups as “gene and chromosome mutations”. 



In sexual reproduction of organisms, sperm and ovule play their parts.  Those two cells combine and produce one-celled zygote. It brings forth the multi-celled organism by developing. The number of chromosomes in the sperm and ovular cells halves before they combine. Thus, when two cells whose number of chromosome have halved combine, the number of chromosomes of this new organism remains unchanged and fixed.  Reduction of the number of chromosomes by half in male and female cells before insemination takes place in plants, animals and in human bodies in the same way as a law. 



Mutation is the alteration which occurs in the genetic constitution of an organism. This might occur on chromosomes or on genes. The alteration on chromosomes occurs in the number of chromosomes or in their constitution. The number of chromosomes of each organism is fixed. The alteration of the number of chromosomes might take place as an increase or a decrease.  For example, in a plant which has 40 chromosomes, this number can change in some individuals due to such reasons as inappropriate division of chromosomes during reproduction or their misreplacemet. For instance, it might become 41 or 42, or 39 or 38. Individuals that have such abnormality of numeric change of chromosomes will not have a healthy life. Most of the time their generations do not continue, and generally such changes cause abnormalities and even death of organisms. 



Another change might occur as an increase in the number of chromosomes exact number of times or half. During the reproduction process of a plant having 40 chromosomes, the number of chromosomes needs to halve while generating pollens and ovule because, when pollen which represents male individual and ovule merge, the number of chromosomes needs to remain fixed as 40. During this reduction by half of chromosomes in a cell, this reduction can be obstructed by interference. As this reduction by half can be made in ovule, it also can be achieved in a sperm cell or in both. In this case, this results in production of individuals with 60 or 80 chromosomes instead of 40. Such increase of chromosomes does not kill the individuals. Their generations continue as well. Such type of chromosomal change is called useful mutation. This method is applied especially in taming plants and animals. For example, corns whose number of chromosomes has increased two or four times, have bigger cobs and larger-grains in comparison to normal individuals. In the same way, in order to improve milk and meat production, similar applications are carried out on animals. 



Mutations apart from this are harmful and usually mortal whether they take place in genes or in the structure of chromosomes. It is possible to encounter different viewpoints which are in favor of or against the hypothesis that in time, mutations brought forth different diversity of organisms which are present today from one ancestor. Whatever the reason, some scientists accept mutations as “raw material for natural selection and “ a prominent factor for evolution” no matter what the reason is (1).



Dobzhansky, a well-known evolutionist, attributes all these changes to mutation and says:



“If all the things have been sprung up from one organism, all organic differences must occur by means of mutational changes” (2) 



Ernst Mayer makes a similar statement:



Mutation is the final source for the  genetic variations which exist in natural populations”. (3)



Waddington claims that mutations which occur randomly are the only cause for differentiation and states it as follows:



We do not know any other way other than mutations which randomly occur for the occurrence of new variations related to heredity. These facts have not changed yet.” (4)



However, there are also many scientists who state that mutations do not provide sufficient evidence for evolution. Among them, Ayala puts forth this statement:



“We predict that the frequency of mutations in higher organisms changes from one per ten thousand to one per million for a single gene.” (5)



Muller expresses this view:



“More than %99 of mutations is definitely harmful. This is all that is supposed to come out of random events.” (6)



The evolut,onist Huxley also points out that mutations are destructive and lethal:



Rarely is one useful mutation encountered out of a thousand of them. However, even this rate is a success because most of the mutations are lethal and some are destructive.” (7) 



A number of different experiments have been carried out on bacteria especially in recent years. The effects of heat, drought, lyophilization, electricity, high pressure and various chemicals on bacteria have been researched. In conclusion, it has been observed that no new species came out by means of mutations in different environmental circumstances. (8)



Bacteria are the organisms which undergo mutation the most frequently. Especially the bacterium, Echerichia coli divides once in twenty minutes. A great amount of bacteria have been produced as a result of experiments which have been carried out in the last 50 years. Furthermore, the number of bacteria produced in these 50 years is much more greater than the number of any species of animal which have survived for 100 millions of years so far.  If a change of species due to mutation could have occurred, such change of species would have been definitely observed on these bacteria.



Institute of Medical Physics and Palynology in the University of Geesser points out that there is no difference between bacteria which existed 500 millions of years and the bacteria which are present today. (9) 



In fact, it is frequently pointed out that it is impossible to explain the form of evolution which is coordinated and has been proceed in a certain direction with randomly and irregularly occurring mutations. (9-10)



Moor states that changes which may occur due to mutations cannot exceed the limits of species and says:



Mutations are the changes which occur in any species of living organisms and which cannot exceed the limitations of species. Groups of macro-organisms can be explained by neither change of polyploidy nor change of chromosomal order.” (12) 



Stephen Gould, a well-known evolutionist, states that a new species cannot be reproduced by mutation:



A mutation cannot produce a new DNA. For this reason, it is impossible to generate new species by mutating species.” (13)



Gordon Taylor, a geneticist and evolutionist, admits the failure of experiments of mutation to provide evidence for evolution and says:



“ For sixty years, geneticists from all around the world have been trying to produce fruit flies to prove evolution. However, they have not observed an occurrence of a species nor an enzyme.” (14)



Conclusion



Useful mutations are the ones which occur as an increase of number of chromosomes in exact number of times. This method is applied in taming plants and animals, production of larger fruits and improvement of milk and meat production. However, it is impossible to reproduce new and different species out of these. Duplicating the number of chromosomes of a corn brings forth larger-grained and bigger cobbed corns and the  corn still remains a corn and the corn does not produce beans. 



Footnotes:



1. Demirsoy, A. Kalıtım ve Evrim. Meteksan Yay. No.11. Ankara. 1984. 



2. Dobzhansky,T.Genetic of the Evolotionary Process.Colombia Uni.Press.1970,P.30. 



3. Mayer,E. Populations, Species and Evolution. Cambridge, Mass: Harward  Uni. 1970, p.102.



4. Waddington,C. H. The Nature of Life. At­heneum. New York, 1962, p. 98. 



5. Ayala, J.F. Teological Explanations in Evolutionary Biology. Philosophy of Science. 1970, Vo1:37.p.3.



6. Muller, H.J. Radiation Damage to the Genetic Ma­terial. American Scientist. 1950, Vo1.37.p.3.



7. Huxley, J.  Evolution in Action. New York.Harper Bros. 1953, p. 4l.         



8. Bilgehan, H. Genel Mikrobiyoloji ve Bağışıklık Bi­limi. Ankara. 1984.                         



9. Şengün, A. Evolusyon. İstanbul Üniv.Yayınları, İstanbul. 1971, issue. 162.



10. Akbult, Ş.  Darwin ve Evrim Teorisi. Yeni Asya Ya­yınları. İstanbul, 1980.



11. Metin,A., Fıeld, A. N. ve Moore, J. N. İlmi Ger­çekler ışığında Darwinizm. Otağ Matbaası. 1976.



12. Moor, J. On Chromosomes, Mutations and Phlo­geny. 1971. Terc. A. Metin. İlmi Gerçekler ışığında Darwinizm. Otağ Yay. 1971.                              



13. Gould, S.J. Is a New and General Theory of Evolution Emerging? Lecture at Hobart & Wm Smith College, 4 Şubat, 1980.                                                                         



14. Taylor, G. The Great Evolution Mystery. New York. Harper , 1983, p.48.

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