This is the most important and misunderstood theory of evolution. It is this insight that ultimately falsified Darwinism back in the 1960s. Neutral theory vs. pan-adaptionalism.
The study of any biological features, including genomic sequences, typically revolves around the question: what is this for? However, population genetic theory, combined with the data of comparative genomics, clearly indicates that such a “pan-adaptationist” approach is a fallacy. The proper question is: how has this sequence evolved? And the proper null hypothesis posits that it is a result of neutral evolution: that is, it survives by sheer chance provided that it is not deleterious enough to be efficiently purged by purifying selection. To claim adaptation, the neutral null has to be falsified. The adaptationist fallacy can be costly, inducing biologists to relentlessly seek function where there is none.
If you care about understanding the science of evolution, this is a must read paper. Over at Sandwalk, they are saying the same thing:
I’m happy to answer any questions that arise.