An article published early this year (2009) in the Science journal proposes that evolution can become predictable, or even manufactured, since evolutionary significant mutations occur only within a select type of genes. The main evidence for this claim comes from parallel evolution, which describes genetic mutations causing the same phenotypic change independently across different species. The article reviews current scientific literature to support this hypothesis such as resistance to DDT reported in 11 different insect species within the same amino acid pathways. This evidence becomes more significant as more than half of evolutionary relevant mutations in plants and animals have been cases of parallel evolution.
However, when parallelism is observed, it is only a specific type of genes that produces the same phenotypic effect, even when many other available genes in the genome code for the same proteins. The key to identifying these genes is arrived at by reviewing developmental biology principals. During development, genes act together to produce the different organs simultaneously. At these stages, there exist input-output genes which relay information from many pathways onto a number of other genes controlling a specific area of development. A mutation in this coordinating gene would change the phenotype in one step and not affect other organs. Whereas the same change by pleiotropic mutations would require many steps, affect other organs, and would most likely be harmful. Moreover, even if pleiotropic mutations produced a positive phenotype, other mutated protein products would likely be harmful and the mutation overall would not favor survival within the population
The literature suggests that most evolutionary significant mutations occur in few specific genes, and that evolution may not be a completely random process after all. If this theory holds, scientific research could certainly be able to identify these genes and induce favorable mutations. This could be implemented in the already controversial genetically modified food industry, or promote unethical experimentation on human subjects.
However, when parallelism is observed, it is only a specific type of genes that produces the same phenotypic effect, even when many other available genes in the genome code for the same proteins. The key to identifying these genes is arrived at by reviewing developmental biology principals. During development, genes act together to produce the different organs simultaneously. At these stages, there exist input-output genes which relay information from many pathways onto a number of other genes controlling a specific area of development. A mutation in this coordinating gene would change the phenotype in one step and not affect other organs. Whereas the same change by pleiotropic mutations would require many steps, affect other organs, and would most likely be harmful. Moreover, even if pleiotropic mutations produced a positive phenotype, other mutated protein products would likely be harmful and the mutation overall would not favor survival within the population
The literature suggests that most evolutionary significant mutations occur in few specific genes, and that evolution may not be a completely random process after all. If this theory holds, scientific research could certainly be able to identify these genes and induce favorable mutations. This could be implemented in the already controversial genetically modified food industry, or promote unethical experimentation on human subjects.
Referenced Article
