Mystery of Genome

Page 31

Are random mutations good?

17

The overwhelmingly deleterious nature of mutations can be seen by the incredible scarcity of clear cases of informationcreating mutations. It must be understood that scientists have a very sensitive and extensive network for detecting informationcreating mutations – most scientists are diligently keeping their eyes open for them all the time. This has been true for about 100 years. The sensitivity of this observational network is such that even if only one mutation out of a million really unambiguously creates new information (apart from fine-tuning), the literature should be absolutely over-flowing with reports of this. Yet I am still not convinced there is a single, crystal-clear example of a known mutation which unambiguously created information. There are certainly many mutations which have been described as “beneficial”, but most of these beneficial mutations have not created information, but rather have destroyed it. For illustration, some of us (like me) would view a broken car alarm as “beneficial”. However, such random changes, although they might be found to be “desirable”, still represent a breakdown - not the creation of a new functional feature. Information decreases. This is the actual case, for example, in chromosomal mutations for antibiotic resistances in bacteria, where cell functions are routinely lost. The resistant bacterium has not evolved – in fact it has digressed genetically and is defective. Such a mutant strain is rapidly replaced by “superior” (i.e. natural) bacteria as soon as the antibiotic is removed. Another example would be the hairless Chihuahua dog. In extreme heat, reduction of size and loss of hair may be useful adaptation, but this involves degeneration, not creation of new information. In such situations, although local adaptation is occurring, information is actually being lost - not added. Yet the Primary Axiom still insists that mutations are good, and are the building blocks with which evolution creates the galaxy of information which currently exists


Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.