Abstract

GARCIA, LUIS FERNANDO. Genes and Evolution, the Thin Thread that Connects Us for Billions of Years. Acta biol.Colomb. [online]. 2011, vol.16, n.3, pp.71-88. ISSN 0120-548X.

The temporal scale of our daily life is a small fraction of the evolutionary history of organisms, including the humans. The planet age is estimated in 4.5 billion years, in which profound changes in the position of continents and the climate of the earth occurred. Nevertheless, most drastic changes arose just in the last 500 million years. The genetics has been a fundamental tool to infer the organismal change throughout billions, thousands and millions of years, for example through the estimation of divergence times. Living organisms share the genetic material as a molecular fingerprint to trace changes in the past. Thus, by using DNA and protein sequences, scientists may understand how the living organisms have evolved, when important evolutionary novelties arose, how genes interact, and determine the evolutionary relationships between past and contemporary forms. The relationships among organisms are inferred by simple similarity (phenetic relationships), by sharing unique features and throughout mathematical models that describe how DNA sequences or proteins evolve (phylogenetic relationships). Genetics also evidences the dynamics of genomes (duplication, transposition, recombination, inversions) that results in gene gain and loss, new functions, and horizontal gene transfer, mechanisms that increase today’s existing diversity. Although the environment is fundamental in the evolution of organisms, it is essential to recognize that there is a very thin and strong thread that connects us inevitably to those first molecules formed in the distant past.

Keywords : Evolution; genome; genetics; horizontal gene transfer; mutation.

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