====== DNA evolution ======

DNA, first isolated (though not yet named and described) in 1869, is the complex, self-replicating, double helix, chemical compound which carries the coded instructions for the development, functioning, growth and reproduction of all known organisms (and many viruses).

In discussions about the [[content:life_sciences:life_itself:primordial_soup|origins of life]] the question arises as to when (and how) it first appeared in the (estimated) 4 billion year history of life on Earth.

The  [[https://en.wikipedia.org/wiki/RNA_world|RNA World Hypothesis ]]suggests that DNA evolved from RNA (a single stranded coded compound that can also self-replicate)  but the details of exactly how this could happen are currently unclear.

>The properties of RNA make the idea of the RNA world hypothesis conceptually plausible, though its general acceptance as an explanation for the origin of life requires further evidence.\\ See : [[https://en.wikipedia.org/wiki/RNA_world#Evolution_of_DNA|Wikipedia]]