27 January 2013

How Organisms Evolve New Functions (Theory and Research)

"Evolution in Four Dimensions", trace four 'dimensions' in evolution: 
* Genetic
Epigenetic (or non-DNA cellular transmission of traits)
Symbolic (transmission through language and other forms of symbolic communication). 

Eva Jablonka and Marion Lamb argue that there is more to heredity than genes. These systems, they argue, can all provide variations on which natural selection can act. Evolution in Four Dimensions offers a richer, more complex view of evolution than the gene-based, one-dimensional view held by many today. The new synthesis advanced by Jablonka and Lamb makes clear that induced and acquired changes also play a role in evolution.

Source: Lecture (bloggpost)


A team of researchers has documented the step-by-step process in which an organisms evolve new functions. The research decodes how E. colibacteria supplement a traditional diet of glucose with an extra course of citrate.

The 1st stage was potentiation, when the E. coli accumulated at least two mutations that set the stage for later events. The 2nd step, actualization, is when the bacteria first began eating citrate, but only just barely nibbling at it. The 3rd final stage, refinement, involved mutations that greatly improved the initially weak function. This allowed the citrate eaters to wolf down their new food source and to become dominant in the population.

Source: link1, link2

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