Copying confusion
Does duplication of existing DNA help evolution?
by Alexander Williams
Molecules-to-man evolution requires the production of large amounts of new genetic
information. In searching for possible mechanisms, evolutionists have sometimes
pointed to the ability of cells to make, and retain, multiple copies of their DNA.
Every time a cell divides, the DNA is copied and the new copy is usually passed
on to the daughter cell. But it can sometimes happen that the copy remains in the
parent cell. When a whole set of chromosomes is copied and retained in this way,
the condition is called ‘polyploidy’. Some defenders of evolution have
tried to claim that this is an example of the ‘new information’ creationists
ask (so far in vain) to see proof of, if evolution is to have credibility. However,
informed evolutionists generally realize that photocopying a page adds no new information;
it just duplicates it.
However, many evolutionists have argued that this ‘extra’ DNA from chromosome
duplication can provide at least the raw material for mutations to work on. The
‘extra copy’ is supposedly liberated to produce new genetic information
by accidental change, in addition to the standard information in the original.
If this process had been an important factor in the ‘evolution’ of life,
then we should find that the number of chromosomes and/or the mass of DNA per cell
would increase as you move up the Tree of Life. The organisms with the most DNA
should have had the greatest exposure to mutation and thus the greatest opportunity
for evolutionary advancement. Bacteria and other single-celled organisms should
have the least amount of DNA, and complex organisms like man should have the most.
Is that what we find? Not at all. Some microbes have more chromosomes and more DNA
than man. Man has only a modest 46 chromosomes, falling somewhere in the middle
of the range that goes from 1 chromosome in an ant (quite an advanced organism compared
to a microbe) to over six hundred in some plants.
Some ‘variation within a kind’ can occur by this mechanism. In chrysanthemums,1 for example, the regular number
of chromosomes is 18, but 27, 36, 54, 72, 90 and 198 also occur, together with odd
combinations like 19, 26 and 37. However, a chrysanthemum with 198 chromosomes is
still a chrysanthemum. The variation appears to be limited to species differences
within the genus. Within the palm family Arecaceae2
the standard chromosome number ranges between 26 and 36, except for one genus, Voanioala,
which has around 600. It is not unreasonable to suppose that such extraordinary
polyploidy has contributed to the separation of this genus from its related genera
within the family—all from the one original created kind.3
But surprisingly, the all-time champion of genetic multiplication is a super-giant
bacterium. Epulopiscium fishelsoni is the world’s largest bacterium.
It is half a millimetre long and weighs in at a million times the mass of a typical
bacterium. In fact no-one believed it was a bacterium until genetic tests proved
it. And it has a whopping 25 times as much DNA as a human cell. The number of multiple
copies of one of its genes has been counted and found to be no less than 85,000.4
It is hard to comprehend such numbers, and to think that it all happens inside a
tiny little dot of one of the world’s ‘simplest’ organisms. But
it is much easier to comprehend the fact that, even with genes copied 85,000 times,
Epulopiscium fishelsoni is still a bacterium. Multiple copies of DNA do
not explain the difference between the microbe and the man. It is the information
contained in the genes, not the opportunities for mutation, that makes the difference.
And that points to an intelligent Designer!
References and notes
- Fedorov. A. (Ed.), Bolkoskikh, Z., Grif, V., Matvejeva, T. and
Zakharyeva O., Chromosome Numbers of Flowering Plants, V. L. Komarov Botanical
Institute, Leningrad, p. 83, 1969 [Reprint Koenigstein 1974]. Return to
text.
- Röser, M., Trends in the karyo-evolution of palms. In: Brandham,
P.E. and Bennett, M.D. (Editors), Kew Chromosome Conference IV, Royal Botanic
Gardens, Kew, pp. 249–265, 1995. Return to text.
- In contrast to plants and microbes, animals do not tolerate chromosome
duplication well, even in part. For example, in humans, an extra chromosome number
21 results in Down’s syndrome. Plants seem
to have been created with the capacity for spontaneous polyploidy and many of our
most useful agricultural plants are polyploid (e.g. wheat). Return to
text.
- Randerson J., Record breaker, New Scientist 174(2346):14,
8 June 2002. Return to text.
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