DNA may undergo mutation during replication. This entails the change of one or more Nucleic Acids in the DNA sequence.

The overwhelming majority of mutations destroy the gene and are lethal to the offspring. Succesful mutation is often a&result of the change acting on a previously duplicated gene.

Any science has to live with the terminology handed down by those who nurtured it in its youth. Biology is certainly no exception, and is riddled with terms that can be vague, confusing and even harmful.

One such word is 'Mutation' which has connotations of mutants and radioactive waste (and possibly superpowers, depending on). This is because biology is rooted in disease and illness - not just a colourful metaphor. One of the most important things to know about the body is what happens when it goes wrong. So those mutations that lead to disease were the first to be noticed and recorded; leading to a pejorative flavour for the word.

So, are all mutations harmful? This is a question beloved of creationists because it implies the answer 'yes'. This veiwpoint has organisms so finely balanced that any change will 'wreak havoc' on the carefully designed structure. Considering the huge range of disorders that are afflict upon us by our genes, this fear of change is unsurprising.

This leaves a minor problem; why aren't we all the same? I have often noticed the dissimilarity between me and my neighbours (no, not because I'm a twisted, mutant mad scientist...). If any change to the 'blueprints' of a human leads to disease, how can you have more than one variation? Also, I will reluctantly admit that there are those who are genetically better at some things than me - olympic runners with more leg muscle fibers for example. It seems reasonable, therefore for my children to 'mutate' into athletes.

There does not seem to be any difference between variation in a species and mutation. What must be recognised is that change is not intrinsically good or bad - it must be taken in context of the whole system. It so happens that biosystems are adept at managing change - by design. Whether you consider the design to be blind or not is your choice.

The idea that mutations are always harmful can be trivially demonstrated to be false. Several types of antibiotic resistance in bacteria are due to mutations in the the DNA coding for proteins attacked by the antibiotic in question. These mutations may have arisen millions of years ago, or they may be novel. As noted by sdanic, gene duplication makes this a lot easier - an organism can now allow mutation on one copy of the gene while not suffering any ill-effects if it all goes pear shaped. As an interesting aside, bacteria will often undergo higher rates of mutation while stressed for some reason (being poisoned, starving, similar things), presumably because this increses the chance that they'll come up with something that can get them out of their current predicament. Mutation allows for evolution.

Mu*ta"tion (mU*tA"shun), n. [L. mutatio, fr. mutare to change: cf. F. mutation. See Mutable.]

Change; alteration, either in form or qualities.

The vicissitude or mutations in the superior globe are no fit matter for this present argument.
Bacon.

 

© Webster 1913


Mu*ta"tion (?), n.

1. (Biol.)

Gradual definitely tending variation, such as may be observed in a group of organisms in the fossils of successive geological levels.

2. (Biol.)

(a)

As now employed (first by de Vries), a sudden variation (the offspring differing from its parents in some well-marked character or characters) as distinguished from a gradual variation in which the new characters become fully developed only in the course of many generations. The occurrence of mutations, and the hereditary transmission, under some conditions, of the characters so appearing, are well-established facts; whether the process has played an important part in the evolution of the existing species and other groups of organisms is a disputed question.

(b)

The result of the above process; a suddenly produced variation.

 

© Webster 1913

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