Natural selection variants

Natural selection and classical breeding both employ the same empirical strategy of creating variants and selecting those that perform best— that is the essence of all protein tailoring methods. They differ only in the sources of sequence variation and the methods by which this diversity is tested. 

Animate objects are self-replicating systems containing a genetic code that undergoes mutation and whose variant individuals undergo natural selection. 

Just as nature uses evolution to naturally select enzyme variations that provide an advantage to the host, directed evolution of the amino acid substitution utilize techniques to screen or select for mutant enzymes that perform better than wild-type enzymes. Unlike site-directed mutagenesis, directed evolution techniques do not require a detailed understanding of the enzyme in order to identify useful variants. The techniques of applied molecular evolution however, do require a screening or selection step to identify the individual mutants of interest (Fig. 12.2). 

Therefore, nature works differently - natural evolution works by selecting variants... 

Darwinian evolution is kept in motion by a continual succession of newly arising variation and its modification by natural selection. The search for active substances proceeds through multiple-component simultaneous procedures, in which a restricted variant population is prepared on a microscale by a combinatorial strategy, to be subjected to the new form of selection, that is, collective screening. After a successfully applied unnatural selection of a particular variant with the desired properties, synthesis on a macroscale can take place. In Section 1.4.2.2.1 a static variation is going to be prepared and screened for anti-inflammatory... 

Iridoids and secoiridoids, as it happens in other groups of natural products, may show an ample variety of structures. It is well known that the biochemistry, the physiology, and the morphology of a plant is subdued to evolutional pressure. During millions of years of evolution, countless number of products have been synthesized by different species, and we can wonder what may be the sense for the plant to contain such as enormous amounts of variants in a sort of metabolic orgy that seems to be senseless. We must not forget that the variability is the bases for natural selection. 

Random mutations may be induced in a protein, and the variant proteins with the desired qualities sorted out from the protein mix. Once the variant proteins have been isolated, further mutations and selection of those variants are performed. This process of mutations and selection is called directed evolution because it simulates natural selection and may produce more fit or successful proteins. Another technique used in directed evolution is DNA shuffling, which mixes and matches pieces of variants to produce better protein products. This process is similar to the recombination process that occurs naturally in individual cells during sexual reproduction. 

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