Gemini – Physical – Plexus: MUTATION

The definition given by De Vries (1901) of mutation was that of any heritable change in the hereditary material that cannot be explained by segregation or recombination. The definition of mutation from the knowledge that the hereditary material is DNA and from the proposal of the Double Helix to explain the structure of the hereditary material (Watson and Crick, 1953), would be that a mutation is any change in the nucleotide sequence of DNA. Mutation is the primary source of genetic variability in populations, while recombination by creating new combinations from those generated by mutation is the secondary source of genetic variability.

Somatic mutation affects the somatic cells of the individual. Therefore, mosaic individuals appear, possessing two different cell lines with different genotypes. Once a cell undergoes a mutation, all cells derived from it by mitotic divisions will inherit the mutation (cell inheritance). A mosaic individual originating from a somatic mutation has a group of cells with a different genotype from the rest; the earlier the mutation occurs in the development of the individual, the greater the proportion of cells with a different genotype. If the mutation had occurred after the first division of the zygote (in the two-cell stage), half of the cells of the adult individual would have one genotype and the other half would have a different genotype. Mutations that affect only the cells of the somatic line are not transmitted to the next generation.

Mutations in the germ line affect gamete-producing cells, resulting in gametes with mutations. These mutations are transmitted to the next generation and are of major importance from an evolutionary point of view.

One of the most important questions about mutations is whether they occur in individuals of populations regardless of whether or not they confer any adaptive advantage to the individual, in which case the mutation would have a pre-adaptive character, or if on the contrary, mutations occur as a result of a physiological adaptation of individuals to the environment, in which case the mutation would have a post-adaptive character, since it would be induced by the environment itself.

I invite everyone to read Matias’ post with the topic of the day.

Finally, I encourage everyone to reflect on the concept of the day. No one else but us can re-signify our own being

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