Junk DNA and Genome Evolution

Abstract

Junk DNA (deoxyribonucleic acid) is a remarkably enduring concept considering the difficulty in describing it with a precise undisputed definition and the serious doubts for its usefulness posed by researchers in different biological fields. At the moment, the main value of the junk DNA concept might not depend on what it clearly defines but how it relates with our difficulties in providing satisfying models for the integration of genome organisation, expression and evolution. In a way, junk DNA is not a measure of our knowledge, as much as it reflects our uncertainties. While sanctioning such uncertainties with a specific term might be of very limiting use for areas of research that employ reductionist approaches to mine genomes or find solutions to biomedical and biotechnological problems, the junk DNA concept might still act as enticing fuel for areas that aim to offer an integrative view of biological systems, their diversity and evolutionary history. Key Concepts Some biological concepts are difficult to describe with simple definitions accepted by all scientific fields. Junk DNA is controversial because it is usually defined in virtue of its uselessness for biological systems well being, and it is unclear which is the best demonstration for the lack of function or effect. Junk DNA might directly descend from protogenomic entities in the RNA world. Junk DNA might facilitate genome evolution by promoting evolutionary capacitance. Junk DNA could be better described as vestiges and facilitators of genome evolution.